Soft, Highly Elastic, and Discharge-Current-Controllable Eutectic Gallium-Indium Liquid Metal-Air Battery Operated at Room Temperature

Abstract

Based on a liquid metal (eutectic alloy with 90 wt% gallium and 10 wt% indium) anode, a soft, highly elastic, discharge-current-controllable, cableshaped liquid metal-air battery operated at 25 degrees C, with effective reactions of Ga - 3e(-) -> Ga3+ and O-2 + 2H(2)O + 4e(-) -> 4OH(-) is presented. In the liquid metal electrode, indium is used not only to inhibit the corrosion of gallium in the alkaline electrolyte but also to maintain the liquid state of the anode at room temperature. Thus, the liquid anode can be easily injected into (or extracted from) the battery cavity, leading to an easily renewable anode. In addition, the cable-shaped battery shows a pressure-responsive discharge current, owing to the soft, deformable battery body. Due to the liquid anode and flexible carbon fiber-based cathode, the battery is highly flexible (bending radius < 1 mm) and easily recovers from any degree of bending without electrochemical performance impairment. With its elastic polyacrylic acid-based gel electrolyte, the battery shows high elasticity, stretching by up to 100% (from 12 to 24 cm), excellent shape recovery from stretched states, and a discharge performance retention of 98.87%. Moreover, this paper provides the possibility to develop a deformable battery based on the liquid metal material.