Pillar effect on cyclability enhancement for aqueous lithium ion batteries: a new material of β-vanadium bronze M0.33V2O5 (M = Ag, Na) nanowires

Abstract

Aqueous lithium ion batteries (LIBs) can fundamentally resolve the safety problem arising from the use of highly toxic and flammable organic solvents, and effectively reduce the manufacturing cost. But many reported aqueous lithium ion battery systems have shown poor stability with capacity retention decreasing rapidly. Taking the silver vanadium oxide (SVO) system as an example, this work focuses on the influence of crystal structural stability on the cycle performance of electrode materials in aqueous electrolyte. β-Vanadium bronze M_0.33V₂O₅ (M = Ag, Na) nanowires were fabricated through a facile precursor-treatment route and, for the first time, used as anode candidates for aqueous lithium ion batteries. The electrochemical measurements showed that M_0.33V₂O₅ nanowires with 3D tunneled crystal structure exhibited enhanced cycle performance compared with Ag₂V₄O₁₁ nanobelts with 2D layered crystal structure. This improvement is attributed to the crystallographic “pillar effect” which can prevent the structural collapse and crystallinity loss during lithium insertion and extraction. Therefore, our investigation could be helpful for the future design of new materials with optimum crystal structure and beneficial matrix elements to realize the suppression of structural destruction and, as a result, the improvement of cyclic stability for aqueous lithium ion batteries.