The high speed development of industries such as new energy power, medical instruments, underground exploration, and high power pulses are demanding more and more dielectric capacitors. Polymer-based film capacitors are attracting attention for their high power density, high breakdown field strength, high reliability, low loss, and small size. However, the low energy density due to the low dielectric constant of the polymer itself has limited its application in high-end fields. And polymer is an effective way to enhance the energy density by compounding with other organic or inorganic materials in different ways. This paper introduces the current research status of polymer-based film capacitors compounded with inorganic materials, analyzes the advantages and shortcomings of different compounding methods, and discusses the future development prospects of polymer-based film capacitors.

Sodium acetate trihydrate (SAT) is a solid liquid phase change material that can be used for solar energy photothermal conversion and thermal energy storage. However, the existence of its supercooling leads to the inability to release and utilize the stored latent heat in time. In this work, disodium hydrogen phosphate dodecahydrate (DSP) was used as the molecular nucleating agent. When the amount of DSP was 3%, the supercooling of SAT was reduced to 0.4 ℃. The corresponding phase transition enthalpy and thermal conductivity are 226.08 J/g and 0.63 W/(m·K), respectively. The combination of carbon nanotubes (CNTs) with high solar absorptance and SAT/DSP heat storage unit leads to a device with solar energy photothermal conversion and thermal energy storage SAT/DSP/CNTs, which realizes solar energy thermoelectric generation. This study provides a feasible and effective method for the utilization of solar energy by sodium acetate trihydrate.

The traditional liquid electrolyte produce dendrites at the negative pole cycle, which cause short circuit of the battery. In addition, there areflammab, explos leak. Solid electrolyte can well solve the above safety problems, and have good stability, that replacement of liquid electrolyte. solid state electrolyte needs to satisfy the requirements, such as high ionic conductivity, wide electrochemical window, excellent chemical compatibility, simple preparation process, low cost and so on. Therefore, it is necessary to further develop high performance solid electrolyte and electrode/electrolyte interface modification materials to optimize and improve the electrochemical performance of solid state batteries. Metal organic frameworks and covalent organic frameworks compounds are newly developed porous materials with periodic structure, which have been widely used in the battery field. This paper reviews the applications and research progress of metal organic frameworks and covalent organic frameworks compounds in solid state lithium ion batteries. At last, how to improve the electrochemical performance of metal organic frameworks and covalent organic frameworks solid electrolytes give.

We synthesized two new sulfite-type compounds as the electrolyte additive: (2-oxido-1, 3, 2-dioxathiolan-4-yl) methyl benzene sulfonate (ODMB) and (2-oxido-1, 3, 2-dioxathiolan-4-yl) methyl 4-methyl benzene sulfonate (ODMM). The cells’ electrochemical performances are characterized by C-rate test, charge-discharge test, electrochemical impedance spectroscopy (EIS). TG-FTIR measurements indicate that ODMB and ODMM both have good thermal stability and their decomposition temperature is 256 ℃ and 255 ℃, respectively. The cell with 0.7 wt% ODMB discharge capacity (147.98 mAh/g) remain at 97.51% of its initial discharge capacity (151.76 mAh/g) after 50 cycles. Scanning electron microscope (SEM) results demonstrate that a denser and stable layer is observed. Moreover, the charge transfer impedance of the electrodes significantly decreases. And wettability measurement shows that the 0.7 wt% ODMB electrolyte exhibits superior wettability than the blank electrolyte, which can effectively ameliorate the cells' assembly process.

The electrode/electrolyte interface is a key factor restricting the high specific energy and electrochemical stability of lithium-ion batteries, and its high-temperature stability has an important influence on the electrochemical performance of batteries. This paper reviews the research progress of the improvement for high-temperature stability of lithium-ion batteries in recent years. The main effects of high temperature environment on electrodes and electrolyte of lithium-ion battery were introduced. From the perspective of electrolyte composition, how to design the electrode/electrolyte interface film which is stable at high temperature was analyzed, so as to effectively improve the high-temperature performance of lithium-ion batteries. Finally, the future development and research direction of high-temperature electrolyte for lithium-ion batteries were prospected.

Lithium is an indispensable energy metal in the age of science and technology. The green and efficient development of lithium resources is the key to ensure the healthy development of related industries. With the development of science and technology, a large number of solid lithium resources such as lithium ore are gradually exhausted due to continuous mining and excavation, and liquid lithium resources with large reserves have gradually become the focus of attention. In recent years, researchers have explored a variety of methods to extract lithium from liquid lithium resources such as Li⁺-rich salt lake brines and seawater. Compared with other methods, the adsorption method shows a superior development prospect because of its advantages of no pollution, simple process and recyclability. In this paper, the research progress of lithium ion sieves for lithium extraction by adsorption methods at home and abroad in recent years is reviewed. The chemical structure of manganese based lithium ion sieve and titanium based ion sieve adsorbent, the mechanism of ion embedding/deinterlacing, the preparation method, the doping modification process and different molding technologies are mainly introduced. The future research focus and development direction of manganese-based lithium ion sieve and titanium-based lithium ion sieve adsorbent are further expounded.

Microcrystalline graphite has the disadvantages of poor processability and low initial effect. For that reason, the microcrystalline graphite was modified by high temperature graphitization, carbonization and coating and the ultrahigh molecular carboxymethyl cellulose lithium-ion (CMC) was introduced as dispersant for anode slurry at the same time. Compared with the microcrystalline graphite before modification, the processability and electrochemical performance were greatly improved. The physical properties was characterized by laser particle size analyzer. The structure and surface morphology of microcrystalline graphite was analyzed by SEM. The processability of the material was characterized by the viscosity change of the sample slurry. The electrochemical properties of the samples was tested by means of coin cells. The results showed that the initial efficiency of microcrystalline graphite after graphitization increased from 64.2% to 87.1% and the ratio capacity increased from 275.2 mAh/g to 343.3 mAh/g. The anode slurry of microcrystalline graphite after coating exhibited better stability without no obvious settlement. Besides, the ratio capacity of the microcrystalline graphite after coating increased to 394 mAh/g. After the introduction of the ultra-high molecular CMC, the stability of slurry was ensured and rate performance of cell was obviously improved as a result.

A composite electrode material (CF-MCNT/Ni@Ni(OH)₂) with hierarchical structure composed of cotton fabric (CF), multi-walled carbon nanotubes (MCNT) and core-shell structured nickel@nickel hydroxide (Ni@Ni(OH)₂) was prepared by ultrasound-assisted impregnation-drying, chemical deposition and anodic oxidation. The structure and properties were characterized by means of scanning electron microscopy, X-ray diffraction analysis and electrochemical tests. The results show that the area specific capacitance of the electrode can reach 6 300 mF/cm² (4 927 mF/cm² at 3 mA/cm²) at a current density of 0.5 mA/cm² in 2 mol/L KOH solution, which is higher than that of CF-Ni@Ni(OH)₂, and the charge/discharge cycle performance has also been improved. The introduction of MCNT facilitates the formation of rough conductive layers on the surface of CF, which provides a reference for optimizing the electrode structure to prepare devices with high performance energy storage.

With the update of mobile and portable electronic equipment, people have higher requirements for improving the performance of lithium ion battery. As a key factor affecting the electrochemical performance of lithium storage-anode materials, its latest research has become a hot spot of widespread concern. In this paper, α-Sn(HPO₄)₂·H₂O was exfoliated into Sn(HPO₄)₂ nanosheets (SNS) by intercalation method, which retained the layered crystal structure and exposed more active sites for lithium storage. Furthermore, the SNS obtained by stripping were further combined with Sn nanoparticles with high specific capacity of lithium storage by electroless plating method. The results show that the Sn/SNS composite has better electrochemical performance of lithium storage than SNS. The specific capacity of Sn/SNS-Ⅲ is 475.7 mAh/g at 0.1 A/g current density. The specific discharge capacity is 449.5 mAh/g after 500 cycles at 0.2 A/g current density, and the capacity retention rate is 63.49% after 1000 cycles at 5 A/g current density. This is mainly attributed to the Sn nanoparticles (~10 nm) uniformly distributed on the SNS surface can provide additional lithium storage sites, and the effective support of SNS to the nanoparticles can alleviate the volume expansion during the charging and discharging process, thus Sn/SNS composites exhibits high lithium storage capacity and good cyclic stability.

SiO₂ is considered to be a promising green lithium-ion anode material due to its high theoretical specific capacity (1965 mAh/g), good cycle stability, high abundance and low cost. In fact, when SiO₂ is used as the negative electrode material of a lithium battery, because of the large bond energy between Si-O, it is inert to Li⁺ and does not exhibit good electrochemical performance. However, by surface modification or construction of 3D nanostructures, it exhibits activity against lithium. In order to further understand this anode material, this article reviews the lithiation reaction mechanism of SiO₂ as a lithium-ion anode material, and discusses its electrochemical performance from the aspects of size, structure, composite with metal oxides and surface modification. Finally, the challenges and prospects of SiO₂ as a negative electrode material are proposed.

In this study, a single ion polymer electrolyte of PEGMEM-co-AMPS-Li was developed via free radical polymerization reaction, using 2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and poly (ethylene glycol) methyl ether methacrylate (PEGMEM) as polymeric monomers. Li⁺ was grafted onto copolymer matrix by lithium reaction of lithium hydroxide solution. PEGMEM provides migration path for lithium-ion. Grafting segments of AMPS could effectively inhibit the crystallization of ethylene oxide (EO) chain segments in PEGMEM, and introduce Li⁺ onto copolymer matrix to form single-ion electrolyte. The electrolyte exhibits good lithium-ion migration number and electrochemical window, and good interface compatibility with positive and negative electrodes, demonstrating the potential application value of high-performance single-ion polymer electrolyte in improving the safety and rate cycle stability of lithium-ion battery.

Battery separators are one of the core components of lithium-ion batteries, which are gradually improved and innovated with the development of lithium-ion batteries. As the most commercially available polyolefin-based microporous separators are subject to performance limitations, it is urgent to develop new processes to prepare battery separators with excellent comprehensive performance and optimize the industrial structure of the separators. This article reviews the lithium ion battery separators prepared by nonwoven technology in recent years, including melt-blown, spunbond, wet-laid and electrospinning, evaluates the performance and preparation process of battery separators, lists specific preparation processes, and prospects the development of lithium-ion battery separators.

Silicon-based anodes are the most promising alternative through a combination of high specific capacity, low discharge potentials and low lithium ion diffusion barrier. However, their large volume changes between the charged and discharged states are detrimental to cycling stability. The fabrication of the silicon-based anodes with nano-sized and porous structure is a broad strategy to realize the practical application of the high specific capacity. Nevertheless, the current preparation methods are usually complicated in process, high in cost and low in yield, making them difficult to apply directly to the battery industry. Therefore, the large-scale preparation of silicon-based anodes with excellent electrochemical performance in a low cost method is the key point. Based on this, in this paper, the synthesis of nano-porous silicon anodes using the low-cost silica source materials through magnesium thermal reduction is reviewed, and the future development of silicon anodes in the battery industry is prospected. It will provide very useful information for the study of the practical application of silicon anodes in lithium-ion battery.

The lithium ion ternary anode material has always been a hotspot because of the reason that it combines the characters of the LiNiO₂, LiCoO₂ and LiMnO₂. Nevertheless materials of the different ratios have different advantages and defects. Material of LiNi_0.4Co_0.2Mn_0.4O₂ has a better magnification performance with the relatively poor cycle performance, which is not satisfied with higher demand for daily lives. The electrochemical properties of the material have always been the goal pursued by scholars, who have been making some modified methods such as coating and doping strategies. In this paper, the material of LiNi_0.4Co_0.2Mn_0.4O₂ is prepared by co-precipitation method and modified with NaAlO₂, and the NaAlO₂ coating as a strategy can significantly increase the cycle performance of LiNi_0.4Co_0.2Mn_0.4O₂ by a series of characteristic means and electrochemical tests. The magnification performance and the reasons for improvement in electrochemical performance have been briefly analyzed.

Silicon-based materials have a theoretical capacity of 4200 mAh/g as anodes for lithium-ion batteries, which is considered the most promising anode materials. However, its volume expansion is too large, resulting in poor cycle stability. Using ball milling and carbon-coated way to modify the nano layered polycrystalline silicon sludge of wire-cutting improves its electrochemical performance as a lithium-ion battery anode material. The results show that ball milling significantly reduces the particle size of raw silicon mud. When the current density is 200 mA/g, the first charging specific capacity of C-Si₂₀ (the raw silicon mud which is ball milled for 20 h after carbon-coated) is 1784.2 mAh/g. After 75 cycles, the specific charge capacity is 640 mAh/g, and the charge-discharge coulomb efficiency remains above 98%. The material has pretty good cycle performance and can provide a certain reference for the recycling and reuse of silicon mud waste in the photovoltaic industry.

The evaluation of the thermodynamic properties of electrode materials at a fixed temperature is helpful to accurately describe the performance of lithium ion batteries (LIBS).In order to fully understand the characteristics of layered lithium LiMO₂(M=Co, Ni, Mn), a large number of theoretical calculations has been used to predict the physical and chemical properties of these materials, such as insertion voltage, Li vacancy ordering, Li diffusion, complex transition metal ordering and electron migration path. However, at high power, the battery generates more heat due to high-speed operation, which leads to a series of thermodynamic problems. At present, most studies based on density functional theory (DFT) only consider the thermodynamic properties at 0 K, but ignore the effect of lattice vibration on the properties at high temperature. On the basis of DFT, the relationship between the temperature and the Helmholtz free energy of Li, LiCoO₂ and Li_□CoO₂ is calculated and plotted by accurately simulating the phonon spectrum and lattice vibration of Li,LiCoO₂ and Li_□CoO₂. Accorded to the influence of different temperature, the delithiation potential is modified. It is found that with the increase of temperature, lattice vibration would further cause the decrease of the delithiation potential, which leads to the decrease of the capacity of the cathode material.

Carbon-coated Fe₂O₃ (Fe₂O₃@C) nanospindles are synthesized by the pyrolysis of MIL-88 precursor. When used as the anode for lithium-ion batteries, this kind of Fe₂O₃@C nanospindles materials can not only promote the contact between the anode and electrolyte, and accommodate the volume change during the cycling, but also improve the conductivity of the based materials. Benefiting from the unique carbon-coated framework structure, the Fe₂O₃@C nanospindles materials present a high initial discharge specific capacity of 1 350 mAh/g, and exhibit an excellent cycling performance (the reversible specific capacity of 800 mAh/g after 100 cycles) and an outstanding rate stability.

The graphitic carbon nitride materials are prepared via direct polymerization of urea, thiourea, melamine, respectively, then Si@C₃N₄-u, Si@C₃N₄-t, Si@C₃N₄-m are synthesized by compounding with silicon powder. The morphology and crystal structure of the three raw materials and composite materials are characterized by using SEM, TEM, XRD, XPS, FT-IR and BET, and the electrochemical properties are tested by galvanostatic charge-discharge measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. The results indicate that the electrochemical performance of Si@C₃N₄-t is better than Si@C₃N₄-u and Si@C₃N₄-m. C₃N₄-t has a more suitable lamellar and porous structure, and the residual groups on C₃N₄-t can form hydrogen bonds with silicon particles. Some silicon powder can enter the large pores and the gap between the layers, so the volume effect of silicon can be alleviated and the electrochemical stability of the electrode can be improved. The Si@C₃N₄-t electrode delivers a capacity of 971.7 mAh/g at a current density of 500 mA/g after 200 cycles.

ZnO@ZIF-8 anode materials are prepared by a simple hydrothermal method and characterized by XRD, SEM and TEM. Compared with pure ZnO, the morphology of the electrode material changes obviously. The electrochemical performance test shows the high reversible capacity and excellent cycling stability of the ZnO@ZIF-8 prepared by simple hydrothermal method with the first reversible specific capacity of 1136 mAh/g and 412.3 mAh/g after 50 cycles. The electrochemical performance of ZnO@ZIF-8 is obviously improved compared with that of pure ZnO.

PW/GO phase change materials are prepared by mixing paraffin (PW) and graphene (GO). Then, PW/GO/cement composites are prepared by compounding PW/GO phase change materials with ordinary cement. The surface morphology of PW/GO phase change materials are characterized by field emission scanning electron microscopy (FE-SEM). The molecular structure of PW/GO phase change materials are characterized by Fourier transform infrared spectroscopy (FT-IR). The compressive and flexural properties of PW/GO/cement composites are tested by mechanical universal testing machine. The thermal properties of the composites are analyzed by differential scanning calorimeter, and the thermal adjustment ability of the composites is studied by using a self-made device. SEM and FT-IR analysis show that PW/GO phase change materials are filled with a large amount of PW in the gap of multilayer GO, which are successfully combined, but their molecular structure is unchanged. Adding PW/GO phase change materials could improve the thermal energy storage efficiency of cement-based materials. The compressive strength and flexural strength of cement composites with 30 wt% PW/GO content could reach 33.2 and 5.5 MPa respectively, and the melting value (ΔH_m) and crystallization value (ΔH_f) could reach 34.02 and 33.85 J/g respectively. The incorporation of PW/GO phase change materials could reduce the indoor temperature fluctuation and provide good temperature comfort, showing good application potential.

All solid state lithium ion batteries are prepared by using copolymer PEDOT-co-PEG as the surface modification layer of lithium metal anode and lithium iron phosphate composite anode, garnet type material and polyoxyethane polymer as solid electrolyte. SEM is used to analyze the morphological changes of lithium metal after repeated charge discharge operation. Electrochemical impedance spectroscopy (EIS) is used to study the contact surface stability of modified lithium metal and composite solid electrolyte, and the charge discharge performance and interface stability of all solid state lithium ion battery are studied. The results show that the high current density capacity of all solid state lithium ion batteries rapidly decays due to the formation of lithium dendrites in the process of charging and discharging. The solid electrolyte composed of "garnet type" substance and polyoxyethane polymer has a good contact surface with the modified lithium metal, which could inhibit the formation of lithium dendrite and improve the mechanical properties of all solid state lithium ion batteries. The stability of all solid state lithium ion batteries is significantly improved and the capacity of all solid state lithium ion batteries is slowed down after the modification of lithium metal by PEDOT-co-PEG copolymer.

Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ cathode materials are coated by the different contents of Li₃PO₄ Li⁺-conductor via the typical Sol-Gel method. The crystal structure and micro-morphology of Li₃PO₄ coated LiNi_0.8Co_0.1Mn_0.1O₂ are investigated by the X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate the prepared samples demonstrate the well layered structure and lower cation mixing degree. The Li₃PO₄ is successfully covered on the surface of LiNi_0.8Co_0.1Mn_0.1O₂. In addition, the results of initial charging-discharging, rate capacity and cycling tests for the four samples demonstrate the cathodes after Li₃PO₄ coating deliver the obvious enhanced electrochemical properties than that of the pristine one. The initial coulombic efficiency of pristine cathode could be enhanced from 84.2% to 89.2% when the Li₃PO₄ coating content increases to 2 wt%. Moreover, the 2wt% Li₃PO₄ coated LiNi_0.8Co_0.1Mn_0.1O₂ delivers a discharge capacity of 129.7 mAh/g at 5 C high rate, much larger than that (92.6 mAh/g) of the pristine one. Meanwhile, the 2 wt% Li₃PO₄ coated LiNi_0.8Co_0.1Mn_0.1O₂ respectively demonstrates the capacity retention of 7.1% and 9.9% higher than those of the pristine cathode at 25 ℃ and 45 ℃ condition after 100 cycles.

Cobalt ferrite substituted with Zn²⁺ and Zr⁴⁺ are prepared by sol-gel auto-combustion method using spent Li-ion batteries as raw materials. The crystal structure, morphology, magnetic properties and magnetostrictive properties are explored. The results show that the substituted samples are spinel structure and the morphology of the samples changes compared with cobalt ferrite. With the increase of zinc-zirconium substituting amount, the saturation magnetization, maximum magnetostriction coefficient and maximum strain derivative of the samples firstly increase and then decrease. At the substituting amount x=0.050, the saturation magnetization and maximum strain derivative of the sample at a lower magnetic field strength are 87.56 Am²/kg and -1.81×10^-9 A^-1m, respectively. It is beneficial to the application of ferrite magnetostrictive materials on the pressure sensors and actuators.

The combination of experiments and molecular dynamics simulations is used to study the properties of porous aluminosilicate ceramics. First, the Material Studio software is used to establish the SiO₂∶Al₂O₃chemical molecular ratio of 3∶1, 2∶1, 3∶2, 1∶1, 2∶3, 1∶2, 1∶3 porous aluminosilicate models. Forcite, VAMP and other modules in the software are used to calculate the model's thermal conductivity, density, constant pressure specific heat capacity, porosity and specific surface area data. The results show that as the proportion of Al₂O₃ increases, the density, constant pressure specific heat capacity, thermal conductivity, specific surface area and porosity all increase. Among them, the overall change of constant pressure specific heat capacity and thermal conductivity shows a piecewise linear increase trend, but constant pressure specific heat capacity and pore rate increases slowly. At the same time, in the experiment, the corundum powder (Al₂O₃), diatomaceous earth (SiO₂) and soluble starch are mechanically mixed into a ceramic embryo body. After firing into a porous ceramic, the internal pores of the porous ceramic are observed by SEM. It is found that the thermal properties changes caused by the internal structure changes of porous ceramics and the molecular dynamics simulation results are mutually verified.

Metal sulfides with different sizes,morphologies,and dimensions obtained through various synthesis/preparation strategies were reviewed,as well as their composite materials with graphene/carbon nanotubes,including layered,sandwich,hollow core-shell and/or mixed structures.When applied to the negative electrode of a lithium ion battery,the metal sulfide composite material exhibited excellent electrochemical properties such as higher discharge capacity,good rate characteristics,and stable cycling.In addition,the application and development prospects of metal sulfide composite materials as battery electrode materials were further prospected.

Carbon materials such as graphene and porous carbon have been widely used in the field of electrochemical energy storage. Graphene/porous carbon-based composites with synergistic effect can give full play to the advantages of graphene and porous carbon, and exhibited excellent electrochemical performance as electrode materials of energy storage equipment. The research progress of binary/ternary composites of graphene and porous carbon in recent years was reviewed. A systematic elaboration was made mainly from the aspects of synthesis method, carbon precursor, structure design, structure-activity relationship and application in different energy storage devices. Finally, the research direction was prospected for graphene/porous carbon-based composites.

Silicon is considered to be one of the most promising anode materials for lithium-ion batteries, which has the advantages of high specific capacity, low potential platform and rich reserves. However, the low initial coulomb efficiency limits its application in lithium-ion batteries. Therefore, in this paper, the internal mechanism of low initial coulomb efficiency through literature research was studied, which focused on the review of the methods to improve the initial coulomb efficiency of silicon negative electrode materials from the aspects of coating, pre-lithium, nano technology and electrolyte modification, and the future development trend was also simply prospected.

With the development of portable electronic devices, the demands for energy density and safety of their core components, i.e. lithium ions batteries (LIBs), are becoming much stricter. Since the solid-state battery can avoid the use of combustible organic liquid electrolytes and separators of flammable polyolefin, they show excellent advantages in energy density and safety, which are considered as the next-generation of LIBs. The core technology of solid-state batteries is to develop novel electrolytes with higher ionic conductivity, non-flammability, considerable mechanical properties, flexibility and environmental friendliness. As one of the best electrolytes of solid-state batteries, PEO-based polymers show strong competitiveness. Therefore, in this work, the progress associating to PEO-based polymer electrolytes was summarized and their prospects were presented.

In this paper, SnO₂@hard-carbon composites with nano-single crystal structure were prepared by hydrothermal method by using cellulose as carbon source and SnCl₄·5H₂O as tin source. Its composition and microstructure were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM). Then two anode electrodes were prepared by using PVDF and sodium alginate as binder respectively, and their electrochemical performance was confirmed by galvanostatic charge-discharge test. The results show that the compatibility of sodium alginate and SnO₂@hard-carbon composite is better, and the electrode material has better rate performance and cycle performance. It has a capacity of about 400 mAh/g at high current density of 2 A/g, and the capacity retention is 89% after 100 cycles. After disassembling the coin cell, it was found that the electrode material with sodium alginate as binder still adhered colsely to the Cu foil after several cycles. Sodium alginate is rich in carboxyl groups, which can from a complex with SnO₂ and make the charge-discharge process more stable.

LiVOPO₄ cathode material was synthesized by sol-gel method in this study. The structures and electrochemical properties of the synthesized materials were studied. Present results indicated that pure β-LiVOPO₄ phase crystallized in an orthorhombic Pnma space group after the precursor gel was calcined at a low temperature of 500 ℃. Micrometer-sized LiVOPO₄ material exhibited a superior long-term cyclability during charge-discharge processes. After cycling 300 times at a current dencity of 10 mA/g, the discharge capacity did not decay, retaining a reversible capacity of over 150 mAh/g after 300 cycles. Particularly, the material also retained excellent capacity (100%) upon 1000 cycles at a current dencity of 100 mA/g. The present results show that the LiVOPO₄ could be used as efficient cathode materials for high energy and long-life lithium ion battery.

In the present study, a phase change composite with sensing function was constructed by using starch-derived carbonaceous foam (CF) as skeleton, polypyrrole (PPy) as conductor of heat and electrons, and inorganic and organic mixed phase change materials (PCM) as energy storage media. The temperature change of the phase change composite can be given in the form of an electrical signal in real time. The effects of the amount of PEG with different molecular weights on the energy storage and sensing properties of the composites were investigated. The results of the resistance-temperature-time relationship indicate that CF-PPy-PCM-1000-1, CF-PPy-PCM-8000-0, and CF-PPy-PCM-20000-0 show better sensing performance. The DSC results show that the melting enthalpy of CF-PPy-PCM-8000-0 was 113.29 J/g, and the melting enthalpy of CF-PPy-PCM-20000-0 was 124.44 J/g, both of which had the potential to be applied as phase change energy storage materials. The SEM images show that the PCM adhered to the cell walls of the CF-PPy skeleton. Although there was room for the further increase of the load of PCM, this incomplete filling also ensured that the phase change component in the composite did not leak during the heat storage process to some extent.

In this paper, a new type of negative film forming additive 2D was studied. The effect of 2D on the performance of NMC811/graphite battery was investigated. The comparison was done with the most commonly used commercial negative film forming additive VC. The differential capacity DQ / DV shows that 2D was reduced at about 2.1 V before EC and VC, and a stable SEI film was formed on the graphite negative electrode. Electrochemical impedance spectroscopy (EIS) test shows that the film formation impedance with 2D was significantly lower than that with VC. The test results of the ratio cycle, high temperature storage and high temperature cycle of the NMC811/graphite containing 2D, VC or 2D/VC show that the passivation film of graphite anode with 2D electrolyte battery was more stable, which effectively improved the performance of cycle, storage and magnification of lithium-ion batteries. The voltage and resistance of the battery with 2D electrolyte at 60 ℃ had little change. After 200 weeks of extreme temperature cycle, the capacity loss of the battery without 2D additives reached 15%, and the capacity retention rate of the 2D battery was above 92%.

Copper oxide nanowires were synthesized on copper foil substrate by anodic oxidation method followed by a simple annealing process. The lithium-ion battery without binder was prepared by using it as anode material. The effect of the anodizing time on the morphology and electrochemical properties of the materials was studied. At the rate of 1 C, the CuO nanowires array with anodizing time of 1000 s showed the highest first discharge specific capacity of 1172 mAh/g and the reversible specific capacity of 594 mAh/g. The reversible specific capacity after 500 circles was 607.6 mAh/g, and the reversible capacity retention rate was 102.3%. It proves that the cross-linked 3D CuO nanowire network could provide a stable structure for lithium ion insertion and removal, which could effectively solve the volume expansion problem of copper oxide materials as anode materials for lithium ion batteries, and exhibit excellent rate performance and cycle life.

Aiming at the shortcomings of poor long-cycle performance of SnO₂ lithium ion battery anode materials, amorphous SiO₂ is introduced into SnO₂ material to form SnO₂-SiO₂ nanocomposites. Three-dimensional ordered macroporous SnO₂-SiO₂ nanocomposites are prepared by using polystyrene (PS) colloid as a template. The results show that the crystal structure of 3DOM SnO₂ material is similar to that of 3DOM SnO₂-SiO₂ material, but the long cycle performance of 3DOM SnO₂-SiO₂ material is significantly improved after adding SiO₂. Cycling 100 times at a current density of 500 mAh/g, at which time the charge specific capacity of the 3DOM SnO₂-SiO₂ material with 0% Si is sharply attenuated to 147 mAh/g, and the charge capacity of the 3DOM SnO₂-SiO₂ material with 5% Si is added, the capacity is 654 mAh/g, and the charge capacity of the 3DOM SnO₂-SiO₂ material with 5% Si added after 500 cycles is increased to 728 mAh/g. These results indicate that SiO₂ can improve the long cycle stability of 3DOM SnO₂ materials.

Lithium titanate(Li₄Ti₅O₁₂) is a “zero strain” material that does not form lithium dendrites during charging and discharging, eliminating the potential safety hazard of overcharging. In this paper, the preparation method and structural modification of lithium titanate were systematically introduced. In the synthesis of lithium titanate, the solid phase method is easier and the production efficiency is high, which is more suitable for mass production in industry. The sol-gel method is more complicated, but the obtained lithium titanate material has higher purity and crystallinity. In the modification of lithium titanate materials, nanocrystallization, spheroidization and porosity are increasing the specific capacity of materials by increasing the surface area of materials. Metal/ion doping modification is mainly to improve the conductivity of the material. Different metallic ions have different effects on the specific capacity of the material. The surface composite modification of materials is a comprehensive modification method, which is a modification method to improve the conductivity of materials while improving the specific capacity of materials.

In this paper, Na₂MnPO₄F/C cathode material was prepared from bagasse as a biomass carbon source. The Na₂MnPO₄F/C cathode material was prepared via ball milling and in situ pyrolysis. The preparation conditions of the cathode material were analyzed by characterization with Raman spectroscopy and the optimum preparation conditions of Na₂MnPO₄F/C were 15% carbon source and 600 °C calcination temperature. The materials were characterized by XRD, SEM, EDS and electrochemical measurement techniques. The results show that the material had good crystallinity, and the carbon material was well coated on the surface of the Na₂MnPO₄F polyfluorinated anion material, and did not affect the material structure. The battery was assembled into a button cell for electrochemical performance test. The results show that the electrochemical performance of Na₂MnPO₄F/C material was better than that of Na₂MnPO₄F material. At 0.1 C, the specific capacity of the first ring of Na₂MnPO₄F/C material was 8.71 m Ah/g, while that of Na₂MnPO₄F material was 1.94 m Ah/g. Carbon coating by in-situ pyrolysis could effectively improve the electronic conductivity of the material and increase the capacity.