Reversible Hybrid Aqueous Li−CO<sub>2</sub> Batteries with High Energy Density and Formic Acid Production
Rui Yang, Zhen Peng, Jiafang Xie, Yiyin Huang, Rahul Anil Borse, Xueyuan Wang, Maoxiang Wu, Yaobing Wang
Abstract
Abstract Metal−CO 2 batteries, an attractive technology for both energy storage and CO 2 utilization, are typically classified into organic Li(Na)−CO 2 batteries with a high energy density/output voltage and aqueous Zn−CO 2 batteries with flexible chemical production. However, achieving both high‐efficiency energy storage and flexible chemical production is still challenging. In this study, a reversible hybrid aqueous Li−CO 2 battery is developed, integrating Li with an aqueous phase, which exhibits not only a high operating voltage and energy density but also highly selective formic acid production. Based on a Li plate as the anode, NaCl solution as the aqueous electrolyte, solid electrolyte Li 1.5 Al 0.5 Ge 1.5 P 3 O 12 (LAGP) as a separator and Li + transporter, and a bifunctional Pd‐based electrocatalyst as the cathode, the resulting battery shows a high discharge voltage of up to 2.6 V, an outstanding energy conversion efficiency of above 80 %, and remarkable selectivity of CO 2 ‐to‐HCOOH conversion of up to 97 %. The related reaction mechanism is proposed as CO 2 +2 Li+2 H + ⇌HCOOH+2 Li + .