Highly dispersed silver nanoparticles for performance-enhanced lithium oxygen batteries

Abstract

Aprotic lithium-oxygen batteries possess ultrahigh energy density but suffer from the sluggish decomposition of discharge product, quick depletion of Li anode and cleavage of electrolyte, in close association with oxygen reduction reaction at the cathode. Herein, highly dispersed silver nanoparticles are used to enhance the lithium-oxygen battery with 1.0 M lithium perchlorate in dimethyl sulfoxide. It is observed that film-like amorphous lithium peroxide is formed through surface pathway instead of bulk crystals, due to the incorporation of silver nanoparticles dispersed in the electrolyte, which subsequently accelerates the decomposition of the discharge product by offering more active sites and improved conductivity. The released silver nanoparticles after battery charging can be re-used in the following cycles. Experiments and theoretical calculation further indicate that the suspended silver nanoparticles can adsorb the soluble oxygen reduction intermediates, which are responsible for the alleviation of oxidative cleavage of electrolyte and corrosion of lithium anode. The lifespan of lithium oxygen batteries is therefore significantly extended from 55 to 390 cycles, and the rate performance and full-discharge capacity are also largely enhanced. The battery failure is attributed to the coalescence and growth of silver nanoparticles in the electrolyte, and further improvement on colloid stability is underway.