Realization of Stable Cathode-Electrolyte Interfaces in DMSO Based Li-Air Batteries: Experimental and Theoretical Perspectives

Electrochemical power sources based on metal anodes have specific energy density much higher than conventional Li ion batteries, due to the high energy density of the metal anode (3842mAh/g 1 for Li). Rechargeable aprotic Li-O 2 batteries consume oxygen from the surrounding environment during discharge to form Li oxides on the cathode scaffold, using reactions (1)     [anode] Li(s) ↔ Li + + e − (2)     [cathode] Li + + ½ O 2 (g)+ e− ↔ ½ Li 2 O 2 (s),   (3)     [cathode] Li + + e − + ¼ O 2 (g) ↔ ½ Li 2 O (s),   The cathode reaction requires large over-potentials for charging due to the mass transfer resistance of reagents to the active sites on its surface, decreasing the round trip efficiency, making recharge of the Li-O 2 cell difficult. To overcome these problems, the cathode needs good electrical conductivity and a porous structure that enables facile diffusion of oxygen and can accommodate the reduced oxygen species in the pores. Two significant challenges exist in the use of the traditional activated carbon material as the cathode of the Li-O 2 system. First, in the presence of Li 2 O 2 the carbon electrode becomes relatively unstable even at low voltages (