Intrinsic Stress-strain in Barium Titanate Piezocatalysts Enabling Lithium-Oxygen Batteries with Low Overpotential and Long Life.

Abstract

Rechargeable lithium-oxygen (Li-O2 ) batteries with high theoretical energy density are considered as promising candidates for portable electronic devices and electric vehicles, whereas their commercial application is hindered due to poor cyclic stability caused by the sluggish kinetics and cathode passivation. Herein, the intrinsic stress originated from the growth and decomposition of the discharge product (lithium peroxide, Li2 O2 ) is employed as a microscopic pressure resource to induce the built-in electric field, further improving the reaction kinetics and interfacial Lithium ion (Li+ ) transport during cycling. Piezopotential caused by the intrinsic stress-strain of solid Li2 O2 is capable of providing the driving force for the separation and transport of carriers, enhancing the Li+ transfer, and thus improving the redox reaction kinetics of Li-O2 batteries. Combined with a variety of in situ characterizations, the catalytic mechanism of barium titanate (BTO), a typical piezoelectric material, was systematically investigated, and the effect of stress-strain transformation on the electrochemical reaction kinetics and Li+ interface transport for the Li-O2 batteries is clearly established. The findings provide deep insight into the surface coupling strategy between intrinsic stress and electric fields to regulate the electrochemical reaction kinetics behavior and enhance the interfacial Li+ transport for battery system.