Yang Hanxi

Hydrogen production from catalytic hydrolysis of sodium borohydride solution using nickel boride catalyst

Abstract A highly stable and active nickel boride catalyst (NixB) was prepared and tested for the catalytic hydrolysis of alkaline NaBH4 solution. It was found that after heat treatment at 150°C in vacuum the NixB catalyst shows greatly enhanced catalytic activity and operational stability. In the experimental conditions, the hydrolysis reaction can produce 6.75 wt % hydrogen at 45°C and >4.0 wt % hydrogen even at room temperatures, exhibiting much higher hydrogen storage capacity than currently used alloys for hydrogen storage. Since the NixB catalyst is inexpensive and easy to prepare, it is feasible to use this catalyst in the construction of practical hydrogen generators for portable and in situ applications.

Discussion on the mechanism of sodium storage of different structural types of carbon material

Because of its rich resources and cost advantages, sodium-ion battery has attracted increasing attention in the field of large-scale energy storage. Similar to the lithium-ion battery anode, carbon materials are the most widely studied sodium storage anode materials. However, carbon materials have diverse structures relied on the treatment conditions, resulting in differences in the properties of sodium storage and even the different sodium storage mechanisms. In order to study the relationship between the carbon structure and its storage behavior, this paper comprehensively analyzes the structural characteristics and sodium storage behavior of different carbon materials, discusses the possible electrochemical mechanism, and makes possible analysis of some existing controversial areas. And this paper can also provide a reference for the development of high performance carbon-based sodium storage materials.

A brief analysis on the technology development of the EV batteries

With an eye to the future commercialization of all-electric vehicles, the realizable targets for the near-term, middle-term and long-term developments of power batteries are proposed on the analysis of the state-of-the-art technologies for electrochemical batteries. In view of the battery systems possibly satisfying the performance targets on different stages, a technology roadmap is put forward with an emphasis on the individual and combined contributions of cathode and anode materials to the specific energies of the power batteries including Li-ion and Li-S batteries. Also, possible strategies are discussed for development of advanced materials and technologies for the power batteries. Finally, the safety issue on lithium-ion power batteries is analyzed together with a brief instruction of the safety-enhancing technologies.

One step ball-milling synthesis of LiFePO4 nanoparticles as the cathode material of Li-ion batteries

A one-step synthetic method was used to synthesize Olivline LiFePO4 powders by direct ball milling the stoichiometric mixture of Fe, Li3PO4, and FePO4 powders. XRD and TEM measurements revealed that the as-prepared LiFePO4 powder have a homogeneous Olivine structure and a uniform size distribution of ca. 50 nm. Based on this material, a LiFePO4/C composite was prepared and used for the cathode material of Li-ion batteries. The charge-discharge experiments demonstrated that the LiFePO4/C composite material has a high capacity of 132 mAh/g at 0.1 C and a quite high-rate capability of 95 mAh/g at 1 C. This new ball-milling method may provide a completely green synthetic route for preparing the materials of this type cost-effectively and in large volume.

Recent progress and challenges in the development of Prussian blue analogues as new intercalation cathode materials

As a large family of the lattices with open framework structure, abundant redox-active sites and chemically stable structures, Prussian blue and its analogues (PBAs) can serve in principle as promising insertion cathode materials for a variety of metal ions. This paper reviews the recent progress in the development of PBAs compounds as Li+, Na+ and other multivalent ions (Mg2+, Al3+, Zn2+, Ca2+ and etc.) insertion cathodes, discusses the relationship between the crystal structure of PBAs and their ion insertion behaviors and briefly analyzes the possible strategies for the problems present in the battery applications of PBAs, aiming at promoting the development of a new type of cathode host materials for next generation advanced batteries.

Al 3+ 掺杂0.5Li 2 MnO 3 -0.5LiCo 1/3 Ni 1/3 Mn 1/3 O 2 正极材料的研究

采用聚合热解法制备了掺入3% Al 3+ 的富锂锰基Li[Li 0.2 Co 0.13 Ni 0.13 Mn 0.51 Al 0.03 ]O 2 材料, 经过X射线衍射(XRD)、扫描电镜(SEM)实验表明, 掺入3%Al 3+ 样品仍然保持层状结构, 没有观察到杂质相的存在。在2.0~4.8 V范围内进行恒流充放电测试表明, 掺Al 3+ 样品在30 mA/g的电流密度下, 首周充放电比容量可达349.1和303.8 mAh/g(首次库仑效率87%); 在100 mA/g的电流密度下, 100次循环后, 容量保持率为91.7%, 显示出高的循环稳定性。这些结果表明掺杂Al 3+ 能够在一定程度上提高富锂氧化物材料层状结构的稳定性, 为发展高容量和高稳定性正极材料提供一种新途径。采用聚合热解法制备了掺入3% Al 3+ 的富锂锰基Li[Li 0.2 Co 0.13 Ni 0.13 Mn 0.51 Al 0.03 ]O 2 材料, 经过X射线衍射(XRD)、扫描电镜(SEM)实验表明, 掺入3%Al 3+ 样品仍然保持层状结构, 没有观察到杂质相的存在。在2.0~4.8 V范围内进行恒流充放电测试表明, 掺Al 3+ 样品在30 mA/g的电流密度下, 首周充放电比容量可达349.1和303.8 mAh/g(首次库仑效率87%); 在100 mA/g的电流密度下, 100次循环后, 容量保持率为91.7%, 显示出高的循环稳定性。这些结果表明掺杂Al 3+ 能够在一定程度上提高富锂氧化物材料层状结构的稳定性, 为发展高容量和高稳定性正极材料提供一种新途径。