Stable three-dimensional metal hydride anodes for solid-state lithium storage

Abstract

Since the discovery of metal hydrides as a conversion-type anode in lithium-ion batteries in 2008, many metal hydrides have been investigated for lithium-ion battery anodes. Although much progress has been made, metal hydrides still face severe challenges such as poor first cycle reversibility, low electrical conductivity, and high reactivity with liquid electrolyte. Here we demonstrate a three-dimensional hierarchical metal hydride/graphene composite (LiNa2AlH6/3DG) that shows the best performance among reported metal hydride anodes. LiNa2AlH6 nanoparticles are uniformly anchored on graphene nanosheets which self-assemble into the 3D microflowers hierarchical structure, and exhibit outstanding cycling stability with LiBH4 as a solid electrolyte. An ultra-high capacity of 861 mA h g−1 at the current density of 5 A g−1 and a long cycle life of 500 cycles with capacity retention of 97% are demonstrated. These findings pave the way for designing nanoscale metal hydrides as electrode materials in solid-state lithium batteries.