High performance dual active bismuth-cadmium positive electrode for liquid metal battery

Liquid metal batteries (LMBs), with low cost, long lifetime, straightforward assembly, and high safety endowed by their distinctive three-layer liquid structure, are emerging as a strong contender for large-scale energy storage. The Li||Bi cell exhibits stable cycling performance and significant potential for practical applications. However, the formation of solid Li₃Bi intermetallic compounds at the electrolyte-electrode interface during discharging restrict lithium-ion transfer kinetics, resulting in high polarization and limited rate capability. To address these challenges, we developed a Bi[sbnd]Cd dual-active alloy positive electrode, where the addition of Cd creates liquid pathways to enhance rate performance and improve adaptability to lower operating temperature. The Li|LiF-LiCl-LiBr|Bi₄₀Cd₆₀ cell, operating at 500 °C, retained 70 % of its initial capacity even at a high current density of 800 mA cm⁻². Furthermore, when paired with the LiCl-LiBr-KBr electrolyte (T_m = 310 °C), the Li||Bi₄₀Cd₆₀ cell successfully operated at 380 °C and achieved 300 stable cycles with a discharge capacity of 4.31 Ah at 100 mA cm⁻². This study provides valuable insights into innovative electrode design for high-performance, grid-scale liquid metal batteries, paving the way for more efficient and adaptable energy storage solutions.