With the progress of human society, wearable electronic devices are becoming more and more desired. Furthermore, there is an increasing demand in stretchability of energy storage devices which have been widely applied to electronic skin, implantable sensors and other portable devices. In this work, several preparation strategies for stretchable Lithium-ion batteries and supercapacitors have been systematically introduced and reviewed on the basis of electrodes, common electrolytes for stretchable electrochemical energy storage devices as well as their strengths and weaknesses have been concluded. Besides, the integration of stretchable energy storage devices has also been showed in this paper. Finally, some challenges and perspectives towards the stretchable energy electrochemical storage devices（SEESDs）have been summarized.

 This bimonthly review paper highlights 100 recent published papers on lithium batteries. We searched the Web of Science and found 4457 papers online from Dec. 1，2017 to Jan. 31，2018. 100 of them were selected to be highlighted. High voltage spinel and layered oxide cathode materials are still under extensive investigations for the structure evolution and modifications. Large efforts were devoted to Si and Sn based anode material for the effects of size and composition and electrochemical mechanism. The cycling properties of metallic lithium electrode are improved by designing current collector and surface cover layer. The studies of solid state electrolytes are focus on the method of preparation and the transport mechanism. Additives to liquid electrolyte can help to improve the cell’s stability at elavated temperatures. Modified interface and electrode structure helps to improve the cycling performance of all solid state battery, Li/S battery, Li-air battery. Theoretical works are related to the structure of bulk and interface of materials and the transportation properties. And a few papers related to cell analyses, theoretical simulations, and modeling.

lithium ion battery has been increasingly applied in the field of mobile and stationary energy storage because of its excellent comprehensive performance. There is always a plurality of battery cells in parallel and/or series in practical application, leading to a faster performance degradation than the single cell. In addition to the uneven operating environment (such as temperature uniformity), the inconsistency of performance among the battery cells in the battery pack is the main reason for the rapid decay of the battery pack performance. To screen single cells with uniform characteristics simply, quickly and effectively is the goal of engineering in practice. In this paper, the consistency screening of lithium ion batteries in recent years are reviewed. The concept and definition of the consistency of lithium ion batteries are explored. The rapid and effective screening by cells in series are evaluated.

 Large-scale lithium-ion battery energy storage system is great important for improving the traditional power grid and the efficient utilize of new energy. In order to achieve a large-scale lithium-ion battery energy storage system with high rate, long life and high security, there is an urgent demand for the high performance battery thermal management system. In this paper, the effect of temperature on the performance of lithium-ion battery is summarized. The research of air cooling, liquid cooling, heat pipe cooling and phase change cooling technologies is reviewed. The application and research status of thermal management technology in the lithium-ion battery energy storage system are analyzed. With the increase of the working rate of lithium-ion battery energy storage system, the heat generated increases and a more efficient thermal management system is needed. The next step of research work should focus on these four aspects: The optimization of air cooling system, the cooling system based on a new medium, the economical heat pipe and the multi-objective optimization design.

Polymer electrolytes are one of the key materials in fuel cells. Alkaline exchange membranes (AEMs), which can transport OH ions, have been intensive studied by many research groups. Alkaline environment can facilitate the reduction of oxygen molecules and therefore the non-precious metal catalyst can be used. However, AEMs are still facing some problems. The key problems of AEMs include the insufficient OH conductivity, the relative insufficient alkaline stability and poor mechanical properties. In this mini review, we discussed recent advances in literatures in AEM field, reviewed the strategy to improve the alkaline stability and OH conductivity. We discussed the performance and hydroxide stability of the widely reported cationic head groups, including the quaternary ammonium, imidazolium, spirocyclic quaternary ammonium, pyrrolidinium. Also the function of construction of cross-linked structures, optimization of polymer backbones, and the function of protective groups were discussed. The influence mechanisms of various factors on the alkaline stability are discussed emphatically. In conclusion, AEMs with high alkaline and high OH conductivity can be achieved by constructing the structure of hydrophilic/hydrophobic phase separation, cross-linked structures, or by optimizing polymer backbones with different structural cationic groups.

Phase change materials (PCM) have become one of the hottest topics in the field of thermal energy storage in recent years. However, phase transition processes of most PCM based systems are highly nonlinear, leading to difficulties in solving the problem analytically. Numerical analysis provides a powerful tool to solve such non-linear problems including heat and momentum transfer. This paper gives a state-of-the-art summary of numerical simulation work on the use of Ansys-Fluent, Ansys [These are the same company so need to change.]and PCMexpress software packages in solving phase change materials based energy storage systems in different applications such as buildings. A comparison is made between these different sofatware packages and issues related model establishment, initial conditions and reliability were identified. Moreover, taking account of PCM encapsulation, inorganic PCM supercoiling and phase separation, the development direction of PCM system numerical analysis such as establishing a reasonable model, verifying the simulation results, improving the simulation algorithm, coupling practical conditions and expanding application Fields are also investigated, combining with application and the characteristics of different software packages.

A finite difference method has been used for the thermodynamic analyses of compressed air energy storage in a underground rock cavern. This is based on the mass and energy balance equations and done on a FLAC3D software package. The influences of charge and discharge rates, minimum operating pressure, storage temperature and properties of sealing material on temperature and pressure of compressed air during operation were investigated. The results indicate that the temperature and pressure of the compressed air increase during charge due to heat exchange between compressed air and surrounding rock of the cavern, but decrease during high-pressure gas charge process. The air charge and discharge rates, the minimum operation pressure of the cavern, the inlet air temperature, the material characteristics of the sealing layer are found to be the main factors influencing the compressed air temperature and pressure.

 Mixed bi-material composite electrode based on LiFePO4 and activated carbon (AC) for hybrid electrochemical energy storage (EES) devices was prepared. The EES devices have been constructed by choosing submicron graphite as anode material and optimizing LiFePO4/AC composites with different mass ratios as the cathode. The results showed that binders had great influence on the capacitive properties of AC, and LA133 as one of the water-based binders should be better choice than oily adhesives. Furthermore, the prepared LiFePO4/AC composite cathodes emerged the dual characteristics of capacitor and battery. As the 40% (weight ratio) of LiFePO4 in the composite cathode, the lithium-ion capacitor could reveal high specific energy which is about 4 times comparing with that of AC/AC supercapacitor (about 40 W·h·kg-1) by computation of the total active materials. Also, it could achieve the fast charge-discharge at 10 C rate. In addition, both of the two devices exhibited the similar cyclability with about 75% of capacity retention after about 5000 cycles.

Compared to sensible and latent heat storage, thermochemical heat storage has a higher heat storage density, achieving seasonal heat storage at ambient temperature. This paper concerns a CaO-Ca(OH)2 heat storage system. A 2D axisymmetric transient model was developed to study the exothermic process of the system, which is essential for reactor design and operation condition optimization. The effect of different reaction conditions and reaction bed parameters on the exothermic process was investigated systematically. The results indicated a rapid reaction zone in the reaction bed with the exothermic reaction moving from the inlet to the outlet. The outlet temperature was mainly influenced by the steam pressure and the reaction exothermic power was mainly influenced by the flow rate. The results also showed that the height of reaction bed had no effect on the maximum reaction exothermic power.

Lithium sulfur (Li-S) battery with the high theoretical energy density has been considered as the most promising next generation of rechargeable batteries, being the research hot topic in the last 10 years. However, the cycle and rate performances could not satisfy the actual requirements. Here, di-2,2,2-trifluoroethyl carbonate (DTFEC) has been investigated as electrolyte addictive to improve the electrochemical performances of the Li-S batteries for the first time. The electrochemical test results show that the additive has a great influence on the performance of the battery and which is related to the amount of addition. With 5% DTFEC (volume ratio) added, the sulfur composite (S@pPAN) cathodes exhibit the best cycle stability and rate performance at room temperature. The capacity retention is improved about 20% compared with conventional electrolyte after 200 cycles at 1C and the reversible capacity is maintained at about 1246.3 mA·h·g-1 even at 7 C. This study indicates that DTFEC is a favorable additive in conventional liquid electrolytes for rechargeable lithium sulfur batteries.

MnO2 is deposited on a nickel foam substrate by using the electrodeposition method, and then the conductive polymer PEDOT-PSS is in situ polymerized on its surface, which was designed to format the composite materials. The impact of wrapped conductive polymer layer on the electrochemical properties has been studied with different polymerization time. The morphologies and structures of the composite materials have been characterized by Raman spectrum, scanning electron microscope and transmission electron microscope, respectively. The results of the electrochemical tests show that the P-MnO2-2 composite with electropolymerization for 10s has the highest specific capacity (346.5 F·g1), which is 1.9 times higher than MnO2 electrode (179.1 F·g1). The P-MnO2-2 composite still has a specific capacity of 223.5 F·g1 at the high current density of 6 A·g1. Finally, a flexible symmetrical solid-state supercapacitor has been assembled using the KOH gel-solid electrolyte to light a LED lamp.

Combining the advantages of Lithium ion battery’s high energy density and electric double layer capacitor’s excellent power performance, Lithium ion capacitor has been regarded as one of the most important research area for supercapacitors. Using high capacitance Li2NiO2 as the Li+ resources for negative electrode, composited activated carbon as the positive electrode, a 300 F lithium ion capacitor has been prepared without “lithium foil” during the pre-doping process. The physical and electrochemical performance of Li2NiO2 and the adding amount of Li2NiO2 have been investigated. The results shows that: Li2NiO2 exhibits a distinctively high irreversible capacity of 398 mA·h·g1 with an irreversible capacity ratio of 94.8% during the first cycle. After adding 15%～20% Li2NiO2 for the lithium ion capacitors, it shows more than 75% rate performance at 10A and nearly 91% capacitance retention during the cycle life time. When adding 20% Li2NiO2 at the composite electrode, the cell has nearly 400F capacitance, 15.5W·h·kg1 energy density and 1.3 kW·kg1 power density. Meantime, the simply making process will prompt this kind of lithium ion capacitor to embracing a bright future.

 In the process of lithium-ion power battery electrolyte injection, the electrolyte displacement efficiency directly affects the forming quality of the solid electrolyte interface (SEI) in the subsequent process. Microstructure of porous electrode in lithium-ion battery were reconstructed by four random growth parameter method, and an improved pseudo potential lattice Boltzmann model was used to simulate immiscible displacement in battery liquid injection process to investigate the effect of wall wettability and porosity of electrode structure in lithium-ion cell on the displacement efficiency. Research shows that the wetting property of porous electrode has a significant influence on the displacement efficiency. With the increase of contact angle, displacement efficiency decreases. In single porosity zone, with porosity increases, the displacement efficiency is enhanced and less material is left. However, when the electrolyte flows through the interface between the anode and separator, because of difference of wetting characteristics and porosity, the electrolyte shows different displacement efficiency. The higher porosity zone has seepage in the vertical direction of flow, which reduces the displacement efficiency in other side and formed bubbles to affect the formation of SEI.

Hydrogen storage composite electrode Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3/x% (weight ratio) Ni was prepared by dry method and wet method (x=0～300), the electrochemical properties and PCT characteristics of the alloy electrode were measured by electrochemical method, and the phase structure and micro morphology of the composite hydrogen storage electrode were also analyzed. The results show that when the hydrogen storage electrode was added with hydroxyl nickel powder, the pressure of hydrogen desorption platform of PCT curve at 288 K, 298 K and 308 K were lower than the platform pressure with x=0, in which the platform pressure is small when x=200. There are only CaCu5, LaNi5 phase and Ni phase in the composite hydrogen storage electrode. With the increase of hydroxyl nickel powder content, the diffraction peak of Ni gradually increased, and LaNi5 phase peak height decreased, together with the FWHM broadening. The PCT platform width of the alloy electrode is the biggest and the platform slope is the minimum as x=200. The Mm0.3Ml0.7Ni3.55Co0.75Mn0.4 Al0.3/200%Ni electrode has the best electrochemical performance in the range of the electrode composition studied.

 Spiro quaternary ammonium bromide was synthesized with 1, 4-dibromobutane, anhydrous potassium carbonate, and morpholine employed as starting materials, and serves as the intermediate for the preparation of spiro quaternary ammonium tetrafluoroborate (SQA-BF4) by an anion exchange method. The chemical composition and thermal stability of the as-prepared product were studied by means of Fourier transform infrared spectroscopy (FTIR), liquid chromatography-mass spectrum (LC-MS), nuclear magnetic resonance spectroscopy (NMR), and thermogravimetric analysis (TG). It is revealed that the as-synthesized product is SQA-BF4, which shows high thermal stability (up to 382℃ in N2). When used as the electrolyte for supercapacitors, SQA-BF4 shows better electrochemical properties than the common tetraethylammonium tetrafluoroborate electrolyte. The supercapacitor fabricated with active electrodes and SQA-BF4 electrolyte operates in a wide potential window of 0～3 V, exhibits high specific capacitance of 18.5 F·g-1, and delivers a high energy density of 83.4 W·h·kg1

In this paper, ammonia fuel as energy storage medium is introduced with its advantages of no pollution, high volumetric energy density and convenient transportation and storage in contrast with typical fossil fuels at first. And ammonia fuel energy storage system shows great advantages in large scale and less restriction of geographical conditions when compared with many other traditional energy storage methods. Besides, the energy consumption as well as the energy efficiency of several ammonia synthesis systems is calculated theoretically and industrially. The biggest problem associated with the cyclic and intermittent energy productions like nuclear energy, wind power, solar power and other renewable energy, is the surplus electricity utilization. Finally, this study proposes a new solution, where there are no carbon emissions upstream or downstream, that ammonia fuel could be compounded using valley power or abandoned electricity and then generating electricity when the supply of electricity is insufficient. It’s demonstrated that the life-cycle energy storage efficiency of ammonia fuel system related aforementioned synthesis process is 25%～40% and the conversion rate of electric power is 2.5～4.0 kW·h / 10 kW·h.

 To solve the problem of poor heat dissipation in a battery pack of a pure electric bus, its cooling system is considered as the research object in this paper. A mathematical model is established to estimate its heat generation rate, the geometric model of power battery box is established by UG, and the velocity field and temperature field are simulated and analyzed using Star-ccm+. By adding the flow guiding plate, the battery pack is improved for better heat dissipation and the orthogonal experiments are carried out, the simulation results show that the maximum temperature of the single cell in the battery pack is reduced and the temperature uniformity between the cells is also improved.

With the development of the new application fields, the lithium ion battery industry has shown steady and rapid growth in recent years, and its cathode materials have ushered in unprecedented development opportunities. China has a unique advantage in the development and industrialization of positive materials for lithium-ion batteries. It has a perfect industrial chain and a good momentum for sustainable development. More and more cathode species and product types appear on the market. In this paper, the status quo of cathode material standards for lithium ion batteries in China is introduced, the requirements of key technical indicators for different kinds of cathode materials are compared and analyzed, the reasons for the differences of technical indicators are explained, and the shortcomings of individual standards are pointed out. At last, some suggestions about future standardization work for LIB cathode materials are put forward.

In the initial stage of basic research and evaluation of products, electrochemical performances of lithium ion batteries are measured commonly through button cell. Accurate measurements and standard analysis are essential for screening materials, exploring new materials and batteries. Based on previous literature and practical experience, this paper summarizes the assembly, charge-discharge measurements and data analysis of lithium-ion button cell in laboratory.

TX-2 satellite Li-ion Battery produced by SISP was first applicated on GEO satellite. Technical requirements of Li-ion battery with long life and high reliability were put forward.In-orbit management policy and failure isolation technology were put forward to meet the technical requirement.Technical proposal, performance tests, and in-orbit behaviour of the Li-ion battery used onboard TX-2 satellite were introduced in this paper. During in-orbit operation，Li-ion batteries had good performance, good consistence between cell packages and valid in-orbit management policy. The in-orbit date indicated that the Li-ion battery used onboard TX-2 satellite had good in-orbit performances and the battery on ground design was fully valided. The success of launching and in-orbit operation of TX-2 satellite battery provides a foundation for widely using Li-ion battery onboard GEO satellites.

Hydrogen, as a promising clean energy, has long been considered as a bridge connecting fossil energy to renewable energy and an important carrier for the supply and circulation of sustainable energy, leading to significant research and development investment in many countries. Hydrogen production technology is one of the most important technical aspects of the hydrogen utilization. This paper summarizes and analyses the research status and R&D efforts in hydrogen production technologies in China based the patent literature. Then identifies the mainstream technology and problem existed of hydrogen production based on literature review. Recommendations are given for hydrogen production technologies and industrial development in China.