The research progress in electrode suspensions of lithium-ion flow battery (LFB) was reviewed. LFB combines the working principles of lithium-ion battery and the structure characteristics of redox flow battery, with the independent power output and storage capacity, large energy density and comparatively low cost. LFB is suitable for the application in the future grid energy storage systems. For the LFB, the electrode suspension is one of the most important functional materials, because its conductive and rheological properties determine the energy density and rate performance of the battery. The technical bottlenecks and the research focuses were analyzed on the basis of the experimental data. The conductive mechanism, the specific capacity and the rheological properties are the important research contents of the electrode suspension for the establishment of a unified evaluation system.

This bimonthly review paper highlights 100 recent published papers on lithium batteries. We searched the Web of Science and found 1204 papers online from Feb. 1，2015 to Mar. 31，2015. 100 of them were selected to be highlighted. Layered oxide and high voltage spinel cathode materials are still under extensive investigations for the structure evolution and modifications. Large efforts were devoted to Si and Sn based anode material. There are a few papers related to electrolyte additives, solid state electrolyte, Li/S and Li-air batteries, and more papers for analyzing the fading and thermal safety mechanism of the cell.

Energy storage technology and its market prospect have drawn large attentions in recent years, New achievements have been continuously made in technological developments and demonstration activities. How to scientific planning the development of energy storage technology is the important issue facing policymakers. Technology roadmap as an important strategic planning tool now increasingly attracting the attention of energy storage industry. Some countries and organizations have begun to use technology roadmap for future development path and the prospect of research on energy storage technology. This paper summarizes the related international research results, focusing on the research purpose, research methods and the core target, etc.

Adopting metallic flywheels is an important way to promote the applications of flywheel energy storage for its superiorities in power density and reliability. This study is aimed to design and optimize metallic flywheel with FEM, considering stress intensity, metal fatigue, energy storage capacity, energy density and processing technology comprehensively. The designed energy capacity was beyond 20 kW·h using the alloy 35CrMoA. Frequent charge-discharged flywheels use 4 times the safe coefficient to realize high reliability, while high-speed standby flywheels took Fatigue ultimate strength as the criterion to balance the energy capacity and lift-time. By contrast, the dumbbell-shaped cross-section was conducive to a larger moment of inertia with a lighter weight, benefitting for reducing the bearing load. Besides, this paper proposed a novel design of lamina-riveted flywheel, and accessed the influence of the axle hole and screw holes. All the above discussion provided available references for the further design and mass production of low-speed/high-power metallic flywheels.

PEO-based solid composite electrolyte with the fast ion conductor LAGP(Li_1.5Al_0.5Ge_1.5(PO₄)₃) as a main ionic conductive component and PEO as the binder were prepared by the solution casting method with fixed n(EO)/n(Li)=13, but varying ratio of LiTFSI to LAGP. The structure and morphology of the solid composite electrolyte were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The conductivity of LAGP-PEO(LiTFSI) electrolyte was analyzed by electrical impedance spectroscopy (EIS). The results show that LAGP is partially complexed with PEO(LiTFSI) and homogeneously distributed in PEO(LiTFSI). Three phases are present, a pure crystalline LAGP phase, amorphous PEO(LiTFSI) phase and a transition phase of the LAGP particles and amorphous PEO(LiTFSI). With w(LAGP)∶w(PEO)=6∶4, the optimal ionic conductivity for LAGP-PEO(LiTFSI) solid composite electrolyte is 2.68×10^-5 S/cm at room temperature and 1.86×10^-4 S/cm at 373 K which is close to the LAGP. It means that the LAGP addition contributes to the improvements of ionic conductivity not only by prohibiting crystallization but also due to its own ionic conductivity.

It is necessary to improve the friendly of the battery energy storage system for large scale grid connected wind system and reduce the negative impact of the wind power fluctuation on the power grid. Based on the battery charged state and wind electric power measurements and the slow time constant and battery energy storage system power identification, we proposed an adaptive control strategy for calming wind power fluctuations. Verified by simulation, this strategy can effectively avoid the fluctuation of battery charged state, prolong the service life of battery, so as to reduce the capacity of the battery energy storage system, maximize the role of battery energy storage system.

In this study, the synthesis of the spinel structure lithium manganese oxide (LiMn₂O₄) by supercritical-hydrothermal (SH) accelerated solid state reaction (SSR) route is reported. The effects of the reaction pressure, temperature and the calcination temperature on the purity, morphology and electrochemical properties of the prepared LiMn₂O₄materials were studied. The experimental results showed that the prepared LiMn₂O₄ materials with 15 minutes reaction in the SH route at 400 ℃ and 30 MPa with additional 3 h calcinations at 700 ℃ exhibited good crystallinity, uniform size distribution and good electrochemical performance. The initial specific capacity reached 125 mA·h/g at 0.1 C, and good cycle performance was shown after 50 cycles at 1 C.

Compared with traditional lithium-ion battery, a battery using lithium titanate anode shows the performance of fast charging and high rate discharge capability, long calendar life, while the cost per A?h is relatively high. It analyses the requirements of a typical power-type MW-class energy storage system for the scope of the C-rate and capacity. Considering the advantages of lithium titanate battery for high power applications, it is concluded that obvious less high-rate lithium titanate battery is needed in a power-type system compared with traditional lithium-ion battery. It can translate into the competitive advantage of the energy storage system.

In this paper, we selected VC (vinylene carbonate), FEC (fluorinated ethylene carbonate), DOL (1,3-dioxolane), DOX (1,4-dioxane), BSC (benzenesulfonyl chloride) as the additives for electrolytes. 18650 type Li-ion cells using the electrolytes with varying amount of additives were assembled and stored in an oven at 55 ℃. The voltage and resistance were measured for analyzing the self-discharge. After 45 days stored at 55 ℃, the battery with 1.00% VC additive in the electrolyte showed the best performance, its capacity retention is 95.00%. From X-ray photoelectron spectroscopic analysis, it is observed that the amounts of CH₃OLi and ROLi on the surface of the anode are increased, resulting in forming a stable and compact SEI film, and the self-discharge performance is improved.

In order to evaluate and filter the best low-temperature phase change materials for thermal energy storage, Analytic hierarchy process(AHP) and VlseKriterijumska Optimizacija I Kompromisno Resenjein Serbian (VIKOR) were introduced in the field of phase change material selection. The evaluation system of three levels and six different attributes was constructed and the optimization model based on AHP and VIKOR was established. Meanwhile, the evaluation method and steps were pointed out. Based on this, by the use of established model, ten kinds of low-temperature phase change materials were sorted according to their comprehensive performance. The results show that the established evaluation system and model based on AHP and VIKOR is effective and practical for selecting optimal PCMs. Sodiumacetate trihydrate and stearic acid are found to be the optimal inorganic and organic phase change materials, respectively.

After the suggestion of “rocking chair rechargeable lithium battery” concept by Armand M at 1972, fundamental research on Li-ion batteries has passed 43 years. Deep and comprehensive understandings on materials, electrochemical reaction mechanism, thermodynamics and kinetics of lithium storage, structure evolution, surface and interface reactions, safety and mechanical properties have been achieved continuously, which promote the development of Li-ion batteries and lead to its commercialization. Currently,demandings on improving the performances and extending to broad applications are still very strong. Therefore, it is expected that basic research will be more helpful to provide better solutions, have more precise understandings on the relationship between properties and performances as well as the failure mechanism during fabrication and service, in addition to identify the effects of all creative strategies based on reliable scientific analysis. Moreover, the basic research on Li-ion batteries also enrich the knowledge of solid state electrochemistry, solid state ionics, energy materials, energy physics and nanoscience. As the last paper in this series, scientific problems, new tendency, difficulties, directions and tools for the fundamental research on lithium ion batteries are summarized briefly.

Superconducting magnet energy storage system (SMES) can achieve quick power response with the power grid, which can enhance the stability of power grid and improve the power quality. This paper introduces a 100 kJ/50 kW SMES including the superconducting magnet design, the cooling system, power conditioning system and the monitored control system. In order to verify the performance of this SMES, open-loop power regulation experiments are conducted. The following conclusions can be achieved through the above experiments, that SMES can respond very quickly to exchange power with the power grid. Based on the above analysis and tests and taking the topology of micro-grid demonstration garden of Yunnan electric power grid into consideration, experiment schemes are presented for the application of SMES in micro-grid, which aims to verify the performance and function of SMES when it is applied in micro-grid.