Impact of a Gold Nanocolloid Electrolyte on Li2O2 Morphology and Performance of a Lithium-Oxygen Battery.

Aprotic lithium-oxygen batteries currently suffer from poor cyclic stability and low achievable energy density. Herein, gold nanoparticles capped with mercaptosuccinic acid are dispersed in 1.0 M LiClO4/dimethyl sulfoxide (DMSO) as a novel electrolyte for lithium-oxygen batteries. Morphological and electrochemical analyses indicate that film-like amorphous lithium peroxide is formed using the gold nanocolloid electrolyte instead of bulk crystals in battery discharging, which apparently increases the conductivity and accelerates the decomposition kinetics of discharge products in recharging, accompanied by the release of incorporated gold nanoparticles with the decomposition of lithium peroxide into the electrolyte. Experiments and theoretical calculations further demonstrate that the suspended gold nanoparticles in the electrolyte can adsorb some intermediates generated by an oxygen reduction reaction, which effectively alleviates the cleavage of the electrolyte and impedes the corrosion of the lithium anode. As a result, the life span of lithium-oxygen batteries is dramatically increased from 55 to 438 cycles, and the rate performance and full-discharge capacity are also massively enhanced. The battery failure is attributed to the degradation of gold nanocolloid electrolytes, and further studies on improvement of colloid stability during battery cycling are underway.