Lithium-ion batteries, which have played important role in the extraordinary expansion of the electronic products market, are still under intensive study for applications in sustainable transportation and energy storages. To obtain lithium ion batteries with specific energy > 200 W•h/kg at cell-level, LiNi0.5Mn1.5O4 (LNMO) is one of the most promising candidates for the cathode. It has many advantages, e.g. high operating voltage [ca. 4.7 V (vs. Li/Li+)], reasonable practical capacity (ca. 135 mA•h/g), excellent rate capability, relatively low cost. In this paper, the structural differences of LNMO with two space groups (disordered Fd-3m and ordered P4332) and its associated electrochemical performances are presented. The atomic-level structure, especially in the surface region, of LNMO during the first charge/discharge cycle (3.5—4.9V) is reported in detail. The preparation and modification of LNMO, e.g. synthesis methods, effects of coating and doping are then reviewed. We also propose surface modification of LNMO, which is different from conventional coating and doping. Surface modified LNMO with TiO2 shows that the surface is covered by oxide particles and the few nanometer surface structure is also doped with Ti ions. The influence of surface modification on the electrochemical cycling performance of LNMO at 25 ℃ and 55 ℃ is reported.

Synchrotron X-ray and neutron diffraction facilities are very popular and indispensable scientific resources that provide powerful instruments and experimental techniques for both fundamental and applied researches around the world. X-rays and neutrons interact with matter in different and also complementary ways, and recently have been extensively used for studying energy storage materials at the electronic, atomic and molecular levels, and even extended to engineering scale. In this article, we will briefly introduce synchrotron X-ray and neutron scattering techniques and their difference, similarity and complementarity. Advantages of synchrotron high-energy X-rays will also be presented. The unique and powerful capacity of neutron scattering for hydrogen storage material study will be shown. We also present some examples of in-situ/operando study of the atomic structure evolution of Na1–δNi1/3Fe1/3Mn1/3O2 and LiNi0.5Mn1.5O4 active electrode materials during synthesis and electrochemical intercalation for sodium ion battery and lithium ion battery. Finally, the future perspectives of synchrotron X-ray and neutron diffraction techniques in the field of materials science for energy storage technology will be discussed.

In this report, nano-Si/C anode materials for lithium ion batteries are mainly introduced. The application fields of these materials are briefly analyzed, such as electric vehicles, consumer electronics, energy storage, etc. The advantages and disadvantages of common nano-Si/C anode materials at present are reviewed and compared. The research and technology progress of these materials of are introduced, including the pilot tests of relevant products. The present conditions of nano-Si/C anode materials are sunmarized, and the development trend is prospected.

More efforts are needed to upgrade the performances of lithium-ion batteries (LIBs) for their further applications in various large electrical appliances such as electric vehicles and smart grid as these devices require high capacity, power density, high rate capability and especially safety. Electrode materials are the key to the performance of LIBs. Recently, metal oxides with much higher capacities and better safety have the prospect of becoming alternative anode materials of commercial graphite. However, the intrinsic low charge/ionic conductivity and poor cycling structural stability lead to poor cycling and rate performances, which greatly hinder their commercial applications. To overcome these disadvantages of metal oxide anodes for LIBs, several strategies have been developed during the past decade. Among them, metal oxide hollow micro-nanostructures exhibit excellent electrochemical properties as anode material for LIBs. In this review, we first describe the current commonly preparation methods to synthesize metal oxide hollow structures and comment on their advantages and shortages. According to some typical examples, we show the promising use of metal oxides hollow-structured anode materials for LIBs. Finally, the direction and prospect of metal oxide hollow micro-nanostructures using as anode materials are further discussed.

Nowadays, there is an ever-growing demand for lithium ion batteries (LIBs) with even higher energy densities, safety, and longer cycle life. Electrode materials, such as silicon, tin, and metal oxides, based on either conversion or alloying mechanism have attracted widespread attention for LIB anodes due to their high theoretical capacities. Unlike the conventional intercalation mechanisms, a large irreversible capacity loss (ICL) in the first cycle is one of the prime issues for this type of negative electrodes. Electrolyte decomposition and the consumption of an excess amount of cathode material occur in an irreversible manner for the first cycle, and thereby leading to a low first cycle Columbic efficiency and large initial ICL. Lithium loss in the initial cycles appreciably reduces the energy density and cycling life, severely hindering practical applications in high energy LIBs. Prelithiation provide an effective solution to address these problems above. This review covers origins of irreversible capacity loss in alloying and conversion based materials, key technological developments, and scientific challenges regarding various prelithiation technologies, including physical blending, stabilized lithium-metal powder (SLMP), electrochemical lithiation, self-discharge mechanism, chemical lithiation, and recently new developed anode/cathode prelithiation additives. Furthermore, we also summarize their application for mitigating irreversible capacity loss of silicon based anodes in high energy Li-ion batteries and lithium sulfur batteries. It is highly significant to discuss recent advancements and future prospects of prelithiation technology, which will provide some general academic reference and principles for further development of other energy storage devices, e.g., ion capacitors, sodium ion batteries, potassium ion batteries, and lithium-air batteries.

 Metal air batteries are attractive devices for electrochemical energy storage and conversion because of high energy density. The slow kinetics of the cathodic electrochemical oxygen reduction/evolution is a key factor limiting the performance of metal air batteries, necessitating the use of active catalyst. In this review, we briefly introduce the structure and mechanism of prevailing metal-air batteries and summarize recent progress in applying spinel-type transition metal oxides as cathode catalysts to build metal-air battery.

Owing to the advantages of high energy density and safe aqueous electrolyte, zinc air batteries become an important research direction in developing green energy, which shows great potential in electric vehicles, portable power supply and large electricity storage systems. However, some issues related to electrocatalysts and electrode structure of the air electrode have seriously restricted the commercialization of zinc air batteries. This paper reviews the possible approaches for developing effective air electrode, including electrocatalyst and electrode configuration, and summarizes present status. Moreover, the development of bifunctional electrocatalysts with high activity, good stability and reasonable cost, air electrode design and manufacturing technology, three electrode configuration suitable for mass production in zinc air batteries are the important direction for novel battery technology in the future.

Li metal is a promising anode material due to the high capacity and the low negative electrochemical potential. The uncontrolled dendrite growth during lithium plating/stripping can induce internal short circuit and thermal runaway with potential safety hazards, which cannot meet the increasing demand for safe, high-energy lithium-ion batteries. Solid-state lithium-metal batteries (SLMBs) that use solid electrolytes (SEs) instead of liquid ones could offer high energy density, long cycle life and high safety. However, ionic conductivity, mechanical strength, electrochemical windows, electrode/electrolyte interface of SEs and favorable lithium ionic and electronic conduction pathways in electrode restrict the development of SLMBs. Multilayered electrolyte will combine the speciality of each electrolyte to acquire ideal solid-state lithium metal battery.

Rechargeable sodium-ion batteries have been considered as one of the most promising energy storage technologies, owing to the low cost and natural abundance of sodium in the earth's crust. However, the issues of the large radius and heavy weight of sodium ion limit the migration and reaction of sodium ion during charging and discharging processes. Therefore, development of novel electrode materials with stability and safety is essential for commercialization of sodium-ion batteries. Among the many electrode candidates for sodium-ion batteries, titanium-based layered materials have recently attracted great interest due to their low cost, stability and safety. This paper summarized recent research progress on titanium-based layered materials for sodium-ion batteries, including titanium-based layered anodes, cathodes, and bipolar electrodes. We provided a detailed analysis and discussion of the scientific issues of titanium-based compounds for the sodium storage. Moreover, the future developing trend of sodium-ion batteries were also briefly introduced in this review.

Sodium ion batteries, owing to the advantage of abundant resources and low cost, have captured increasing attention in recent years. National and international companies both at home and abroad have listed sodium ion batteries on the development plan, demonstrating the industrialization in the near future. The same as commercialized lithium ion batteries, conventional organic liquid electrolytes are adopted in sodium ion batteries, providing high ionic conductivity, while also bringing the safety issue such as leakages, fire, ect. Solid-state batteries, using solid electrolyte instead of the traditional organic liquid electrolyte, are the ideal chemical power of electric cars and large-scale energy storage as they have enhanced safety performance and high energy density. The researchers are exploring the solid state sodium batteries and lithium batteries at the same time. The main solid state electrolytes for sodium batteries can be divided into beta-Al2O3, NASICON, sulfide, polymer and boron hydride. In this paper, according to the solid electrolyte type, the development of the solid electrolyte materials and the corresponding solid state sodium batteries are reviewed.

Large-scale energy storage becomes more and more important in the applications of efficient utilization of renewable energy, development of smart grid and improvement of power supply quality. Liquid metal battery (LMB) is a newly developing battery with molten salt and metal/alloy as electrolyte and electrodes, respectively. LMB has potential applications in the large-scale stationary energy storage area, with the merits of low-cost, large-capacity, high-efficiency and long-life, etc. This paper mainly focuses on the R&D progresses of LMB, analyzes the technological challenges and points out the developing direction of novel LMB for large-scale applications.

Material genome is the very important frontier technology in material field, which owns profound scientific content and significant application potential. In the last decades, materials science and technology realized revolutionary leap with the help of materials genome. This technology has been used in energy material fields and reduces the lifecycle of “Discovery-Research and Development—Production—Application”, which owns important significance of application. This paper introduced the progress of two typical materials genome platform of Materials Project and The Open Quantum Materials Database (OQMD), and concluded the guidance technology of material genome used in new energy materials, such as material conformational representation, high throughput calculation and screening, machine learning, nerual network technique and optimization algorithm. Especially put forward, people should increase the integration of high throughput calculation and experiments, and base this and combine industrial 4.0 concept, exerting system fusion effect of material genome technology, sharing big data self-worth, and finally build material genomic large data artificial intelligence system equipped with the ability of self-selection and self-evolution, and establish new model of material development of digital intelligence.

Low-cost and renewable lithium slurry battery is a new type of electrochemical technique for energy storage. The lithium slurry battery is believed to have good application prospect in the fields of low-speed electric vehicles, grid station energy storage and so on. In this paper, the development trend, countries, subjects and key applicants of the lithium slurry battery were analyzed. In addition, the technology layout and patent competitiveness of the patents from the key applicants were also discussed. The relevant patent technology analysis contributes to promote the technology development and industrial implementation in this field.

The failure problems, associated with capacity fade, increased internal resistance, gas generation, electrolyte leakage, short circuit, battery deformation, thermal runaway, lithium deposition and etc., are the major issues that limit the performances, reliability and consistency of the commercialized lithium ion batteries. These problems are the result of a complex interplay of a host of chemical and physical mechanisms. A reliable analysis and fundamental understanding of aging characteristics is of critical significance for development of battery. The failure analysis of lithium ion batteries is started with the identification of the failure effects, then selected the advisable analysis methods to establish the high efficiency procedures to target the problems and thus to find out the primary causes as well as to provide reliable suggestions for further optimization of material fabrication and battery engineering. This article discusses the failure effects and their causes in lithium ion batteries. The procedure of the failure analysis and the inspection methods will also be presented. Some cases of failure analysis are reviewed in this manuscript, such as capacity fade, thermal runaway, and gas generation.

Lithium sulfur batteries, because of their high theoretical specific capacity ~1675mA•h•g1 and energy density ~2600 W•h•kg1, have become the hotspot and keystone of the researches on the next-generation energy storage. Dissolution and the consequent shuttle effect are the main challenges of lithium sulfur batteries which seriously hinder the real application of the batteries. The high solubility of polysulfides in electrolytes generated during the charge-discharge process, results in severe loss of specific capacity. The Li2S2/Li2S deposited on lithium anode also decreases the utilization of active sulfur. Meanwhile, the shuttle is considered as the major reason for the low coulombic efficiency. This review discussed the shuttle mechanism and introduced the recent research progress in physical or chemical shuttle suppression, including the designs related with the cathode, electrolyte and anode. The future research directions and perspective of lithium sulfur batteries were also described.

Supercapacitors are energy storage devices which combine the advantages of secondary batteries and dialectical capacitors. Supercapacitors boast such characteristics as high power density, high charge/discharge efficiency, long cycle life and wide operation temperature. CO2 conversion into various carbon materials is recently developed and is considered as a promising technique towards green fabrication of carbon-based energy-storage materials. This review starts from different strategies for fabricating high-performance carbon-based electrodes, introduces the development of CO2 conversion methods, including direct combustion, high-temperature magnesiothermic reduction and self-propagating high-temperature synthesis, and then gives a detailed discussion of application of CO2-derived carbon in supercapacitors. At the end of this review, the prospect of CO2 conversion in production of carbon materials and fabrication of supercapacitors is given.

High power density and capacity energy storage technology for energy source structure adjustment and the utility of the renewable energy is in urgent need. Owning to the characteristics of separation of the energy and the power, high safety and long cycling life, the flow battery become one of the most promising technology for the large scale energy storage. However, the high cost and the low energy density limit its further development. Mainly focus on the cost reduction and stability improvement，the paper firstly introduce the development status and prospect of the commercialized vanadium flow battery technology and summarize and analyse the developments in the domestic and foreign companies. Then, we overview the current status of the aqueous and nonaqueous flow battery new systems including their characteristics, problems and challenges respectively. Finally, raising the development requirements for flow battery technology with low-cost and high stability and paving the way towards high performance new system.

The study of thermal storage materials is popular all over the world. This article reviews the latest research progress of the material system, preparation technology and performance characteristics of sensible thermal storage materials, latent thermal storage materials and thermochemical thermal storage materials. The composition, structure, preparation process, performance characteristics, existing problems, application prospects and future developing trends of the thermal storage materials were discussed. Each material has its advantages and disadvantages. In order to overcome the disadvantages of the materials and keep their advantages, development of composite material is the new trend in the research and development of thermal energy material. Current preparation technology of novel composite materials are: ① Preparation of microcapsule/Nano capsule using physical and chemical methods; ② Macro-encapsulation method; ③ Preparation of shape-stabilized composite phase change material using mixed-sintering method; ④ Preparation of composite phase change material using impregnation method. The research and application trends of composite thermal storage materials are discussed in this paper.

The technical characteristics, application fields and key technologies of flywheel energy storage system were reviewed briefly, in which the mechanical and structural design of composite flywheel was the fundamental study for improving energy density. In particular analysis, both theoretical analysis and finite element calculation provided stress and strain information of composite flywheel at rated speed, and the ultimate speed was determined according to strength criterion. Some operations, such as multi-rings interference fitting, commingled fiber reinforced structures, multidirectional fiber alignment, winded and woven plies, were selected to enhance the energy density, making full use of the design feasibility of composite to adapt to the stress features in rotating condition. The energy capacity of composite flywheel had increased from 0.3—5 kW•h to 30—130 kW•h, and the energy density had realized 30～100 W•h/kg correspondingly. As contrast, alloy steel flywheel cost 700 $/kW•h and the cost of composite material in flywheel estimated at 3000 $/kW•h. Therefore, the low performance-price ratio restricted composite flywheels from large-scale applications.

 Energy storage plays different roles in the conventional power system, renewable energy power generation, distributed power generation and micro-network, auxiliary services, and thus different income model and economic evaluation methods are used. Economics researche of energy storage technology in domestic and international is still at early stage, and a mature economic evaluation system is still absent. In this paper, the current situation economics research of energy storage in domestic and international, the value and benefit of energy storage in power system, and the research trend of energy storage economy are analyzed.

LiNO3-NaNO3-KNO3 salt was prepared by static melting method. It was calcinated at                      520 ℃, 680 ℃ and 720 ℃ for different time to investigate the influence of heat treatment on solidus temperature of the salt. Differential Scanning calorimeter (DSC) and X-ray diffraction (XRD) were used to characterize the thermo-physical properties and phase. Results show that the solidus temperature of the sample was lowered to 63.0 ℃ after treated at 680 ℃ for 2 h, while alkali metal oxides and nitrite were found.

The demand for energy gradually diversifies on user side along with the development of smart grid. Therefore, demand for diversified energy on user side needs to be taken into account based on economic analysis of electrical energy storage system (ESS). This paper firstly introduces thermal ESS to form an electrical/thermal comprehensive ESS together with electrical ESS considering the users’ demand for thermal energy. Then the economic model of the comprehensive ESS is built and the initial investment cost, average annual cost and annual earnings of new ESS are analyzed. A test case including two scenarios in which the first does not have thermal ESS while the second takes it into consideration is given to compare the economic performance. The results show that introducing thermal ESS will improve the initial investment cost and annual operating cost, but the whole economy of ESS will rise, thus shortening the life of return of investment, which illustrates the necessity and effectiveness of introducing thermal ESS.

The 3rd generation semiconductors like silicon carbide (SiC) and gallium nitride (GaN) which have wide bandgap, high breakdown voltage, high thermal conductivity and fast drift velocity are widely adopted in optoelectronics and high-frequency big-power applications. This paper briefly introduced the physical structure and electrical characteristics of SiC power semiconductors and compared these properties with that of Si power semiconductors. One SiC MOSFETs and one Si MOSFETs were chosen to compare their electrical characteristics, and they were simulated in the laboratory by Saber to compare their power loss in the same circuit. The simulation result showed that SiC MOSFETs experienced 30%—48% less power loss than Si MOSFETs. Finally, several SiC applications in optoelectronics, PV inverters and mobile energy storage power station were discussed. Two applications were tested and analyzed in detail, and the results showed that SiC system had                   50%—60% lower operating temperature, 11% lower power loss, 2.68% higher efficiency and the power density had increased from 0.47 kW/L to 0.90 kW/L. It means SiC components can increase system efficiency and power density dramatically. However, SiC components still have huge potential to increase its performance, and the operation frequency can be boosted to over 500kHz. As a result, the power density of system can be 5 to 10 times greater than the current system.

This bimonthly review paper highlights 100 recent published papers on lithium batteries. We searched the Web of Science and found 1961 papers online from Jun. 1, 2017 to Jul. 31, 2017. 100 of them were selected to be highlighted. Layered oxide and spinel cathode materials are still under extensive investigations for the effects of structure evolution and modificationson their cycling property and thermal stability. Large efforts were devoted to Si and Si based anode material for improving their cycling propeties with new preparation method and optimal working conditions. Their capacity fading mechnism is also analyzed. 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 interface modification. Additives to liquid electrolyte can help to improve the cell’s stability at elavated temperatures. There are a few papers related to Li/S battery, Li-air battery for improving their cycling performance and more papers related to cell analyses, theoretical simulations, and modeling.

This nine months review paper highlights 100 recent published papers on supercapacitors. We searched the Web of Science and found 1811 papers online from October 1, 2016 to June 30, 2017. 100 of them were selected to be highlighted. The researches of electrical double-layer capacitor (EDLC) are mainly focused on new carbon material designed preparation, such as porous carbon materials, graphene, and their effect on supercapacitor performance. The published papers of pseudocapacitor include four aspects, such as metal oxide composites, conductive polymer composite, heteroatom doping carbon materials and new type of pseudocapactive materials. Hybrid supercapacitor includes aqueous hybrid supercapacitor and organic hybrid supercapacitor.

Ministry of Science and Technology of the People’s Republic of China (MOST) initiates national new energy vehicles pilot project in 2015 for next 5 years. Totally 19 projects are announced in 2016. The project 1.2 is a 5-year fundamental research type project (2016—2020), aiming to increase the energy density of EV batteries and to promote the batteries into EV market further. Two targets are purposed: 300 W•h/kg for Li-ion batteries and more than 1000 EVs using the batteries in the market. After 3 rounds review and defense, a team led by Hefei Guoxuan High-tech Power Energy Co. Ltd. wins the project. The title of the project is “Development and Application of Lithium ion Batteries with High Specific Energy Density”. Scientific problems and technologies will be studied: system matching of high nickel cathode and Si-based anode to achieve more than 300 W•h/kg energy density with >1500 cycle life, multilevel security protection of the batteries during integrated application in EVs. This project includes 6 institutes and 6 companies as partners.

 Phase change composite (PCC) thermal control technology is a novel type of lithium-ion power battery thermal management in recent years. The key physical properties of a paraffin/graphite composite PCC were analyzed by SEM, DSC and TG, the results show that the phase transition temperature is about 40 ℃ and the latent heat is about 160 J/g. Before and after adding PCC, the temperature rises of battery modules at different discharge rates were studied numerically and experimentally. The results showed that adding PCC can effectively improve the battery module thermal control ability, although the energy density is somewhat impacted. Therefore, its application in high power output energy system is very promising. Finally, the simulation results show that the composite control strategy with combining phase change material and liquid cooling method is one of the research directions of power lithium ion battery thermal management.