Designing Organic-Borohydride Systems as Solid-State Electrolytes for Alkail-ion microbatteries

Yuqin Fan, Igor E. Golub, Joel Omale, Luc Piraux, Alexandru Vlad, Yasmine Benabed, Geoffroy Hautier, Yaroslav Filinchuk*

Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Place Louis Pasteur 1, 1348 Louvain-la-Neuve, Belgium

Complex borohydride becomes a type of promising solid-state electrolyte applied for rechargeable batteries1. Although LiBH4 can exhibit satisfactory Li-ion conductivity (10-3 S cm-1) over 110 , while LiBH4 only delivers 10-8 S cm-1 at the room temperature, which extremely limits its practical application in all-solid-state batteries. And pervious reports normally focus on inorganic components, like metal oxide or halogen elements, to modify LiBH4 to improve their conductivity. Herein, we combine LiBH4 with borohydrides containing an organic cation, Me4NBH4, Et4NBH4 and nBu4NBH4 to synthesize a series of LiBH4-R4NBH4 system. These obtained compounds exhibit great conductivity due to rotational motions of BH4 and disorder of R4N+. The Me4N(LiBH4)2 can deliver 4.46×10-5 S cm-1 of Li-ion conductivity at 80 with relatively lower activation energy 0.41 eV, it remained stable in the wide potential range from 0-3.5 V. These attempts not only pave a way for the design of new organic-borohydride systems but also achieve a potential and suitable solid electrolyte for Li-ion batteries.1


  1. Cuan, J.; Zhou, Y.; Zhou, T.; Ling, S.; Rui, K.; Guo, Z.; Liu, H.; Yu, X. Advanced Materials 2019, 31 (1), 1803533.