Overcoming sluggish kinetics in bismuth electrodes via electronic networking enabling a 4000-cycle liquid metal battery

Abstract

Liquid metal batteries (LMBs) are emerging as a promising energy storage solution owing to their inherent safety, low cost, and long lifespan. Bismuth (Bi) offers excellent cycle stability but is hindered by sluggish electrode kinetics due to the formation of compact and poorly conductive intermetallics at high rates. Here, we construct an electronically networked architecture to overcome this limitation by incorporating little copper (Cu) into a Bi electrode. This innovative design enhances electrical conductivity and reduces the ion diffusion energy barrier, affording dramatically improved electrochemical performance. Our Li‖Bi₉₆Cu₄ cell demonstrates superior high-rate capability, delivering 85.50% of the theoretical capacity at 3C, a substantial improvement compared to 57.50% of the Li‖Bi cell. Furthermore, it exhibits unprecedented cyclability without noticeable capacity degradation over 4000 cycles, a performance unparalleled by other reported LMB chemistries. This facile and effective Cu doping modification provides a transformative approach to enhance Bi electrode kinetics, offering a new paradigm for advanced electrode design for LMBs.