Application of Metal Hydrides for All-Solid-State Li-Ion Batteries

Abstract

Energy storage have become a crucial topic in the development of the near future technology. Many factors indicate a clear trend in the integration of portable electronics, tools, and electric transportation in our daily activities. The development of the potential of all these applications strongly depends on the development of high energy density storage systems. Metal hydrides represent a promising alternative option to overcome current limitations on the road to future generation batteries. As equal to other under development materials, metal hydrides shown suitable characteristics as Li-ion battery material. Lithium can be stored with a conversion reaction type mechanism. The conversion reaction mechanism in metal hydrides allows to design high energy density electrodes. Due to the low potential of the reactions observed in some metal hydrides (< 1 V vs Li), the application could be focused on the design of negative electrode for li-ion batteries. Similar to other all-solid-state batteries, the performance of metal hydride-based batteries is mainly limited by the low conductivity of solid electrolytes at low temperature applications. Ionic conductivity of solid electrolytes has a high dependency to the working temperature. However, the recent progress in solid electrolytes, e.g. LiBH4 based electrolytes or sulfide based, have allowed the enhancement of metal hydride electrodes. Besides, other limitation observed in these materials is the cyclability. The capacity of the electrodes is drastically lost after some cycles because of the nature of the solid-solid reaction, but different electrode preparations methods have shown some directions to improve the performance of the electrodes. Metal hydrides are still under research but some cases such as MgH2 or TiH2 have been reported with outstanding capacities and promising characteristics as electrode materials.