Pulsed Current Boosts the Stability of the Lithium Metal Anode and the Improvement of Lithium-Oxygen Battery Performance.

ABSTRACT

Lithium-oxygen batteries have received extensive attention due to their high theoretical specific capacity, but problems such as high charging overpotential and poor cycling performance hinder their practical application. Herein, a pulsed current, which merits its relaxation phenomenon, is applied during the charging cycle to address the abovementioned problems. Pulsed charging can not only reduce the charging overpotential, but also control the mass transfer and distribution of lithium ions. As a result, the uniform deposition of lithium ions on the anode surface is realized, the repeated rupture and formation of the solid electrolyte interphase is reduced, and the growth of the lithium dendrites is successfully suppressed, thereby achieving the purpose of protecting lithium metal from excessive consumption. When the pulsed charging duty ratio (Ton/Toff) is 11, after 25 cycles, the lithium-oxygen battery anode still presents a relatively flat and dense deposition surface, which is obviously better than the loose and rough surface after normal cycling. In addition, the protective effect of pulsed charging on the lithium metal anodes of lithium-oxygen batteries is also verified by the construction of other lithium-based batteries.