Advancing Flow Batteries: High Energy Density and Ultra-Fast Charging via Room-Temperature Liquid Metal

Abstract

Global climate change necessitates urgent carbon neutrality. Energy storage is crucial in this effort, but adoption is hindered by current battery technologies due to low energy density, slow charging, and safety issues. A novel liquid metal flow battery using a gallium, indium, and zinc alloy (Ga₈₀In₁₀Zn₁₀, wt.%) is introduced in an alkaline electrolyte with an air electrode. This system offers ultrafast charging comparable to gasoline refueling (<5 min) as demonstrated in the repeated long-term discharging (123 h) process of 317 mAh capacity at the current density of 10 mA cm⁻² with an average voltage of 1.1 V. A high practical capacity density of 635.1 mAh g⁻¹ is achieved in this brand-new battery with a potential theoretical value of 1004.4 mAh g⁻¹. Microscopic and numerical simulations reveal significant hydrogen evolution reaction and dendrite suppression compared to Zn and pure Ga electrodes. The potassium iodide (KI)-modified Ga₈₀In₁₀Zn₁₀-air battery exhibits a reduced charging voltage of 1.77 V and high energy efficiency of 57% at 10 mA cm⁻² over 800 cycles, outperforming conventional Pt/C and Ir/C-based systems with 22% improvement. This innovative battery addresses the limitations of traditional lithium-ion batteries, flow batteries, and Zn-air batteries, contributing advanced energy storage technologies to global carbon neutrality.