Extended cycling performance of micron-sized bismuth anodes for lithium-ion batteries: self-healing of an alloy-type anode for lithium batteries

Abstract

This study investigates the potential of micron-sized Bi as an alloy-type anode material for lithium-ion batteries (LIBs). Compared to the limited capacity of conventional anode materials, Bi offers a high theoretical volumetric capacity of 3800 mA h cm⁻³. We utilized commercial micron-sized Bi powder and a conventional method to prepare Bi electrodes. Remarkably, the Bi anode exhibited excellent cycling stability with a capacity retention of 94% after 1000 cycles when using a tetrahydrofuran (THF)-based electrolyte. During charge/discharge cycling, the Bi particles initially underwent pulverization but subsequently formed a porous structure through room-temperature sintering, showcasing a self-healing phenomenon. Importantly, the pulverization of the alloy-type anode did not contribute significantly to degradation during cycling. This study presents the first evidence of self-healing from pulverization in alloy-type anodes for LIBs. We successfully fabricated a full cell by combining the Bi anode with a lithium iron phosphate (LFP; Li₄FePO₄) cathode. Notably, the results demonstrate the promise of micron-sized Bi without surface coating or nanostructuring as an anode material for LIBs. Additionally, the self-healing concept explored here holds potential for application to other alloy-type anodes in LIBs, providing an avenue for further advancements in next-generation battery systems.