Dual functional mesoporous silica colloidal electrolyte for lithium-oxygen batteries

Dual functional mesoporous silica (mSiO₂) colloidal electrolytes are promising to protect lithium anode and accelerate the reaction kinetics on cathode for lithium-oxygen batteries (LOBs). In this work, we achieved a significantly extended battery life (from 55 to 328 cycles) of LOB by using mSiO₂ with a concentration of 80 mg L⁻¹ in the colloidal electrolyte, compared with the one using conventional LiClO₄/DMSO electrolyte. The rate performance and full-discharge capacity are also dramatically enhanced. The as-synthesized mSiO₂ has a special ordered hexagonal mesoporous structure, with a high specific surface area of 1016.30 m²/g, which can form a stable colloid after mixing with 1.0 M LiClO₄/DMSO. The side reactions of Li stripping/plating are suppressed, thus the cycling life performance of LOB is enhanced by relieving the attack of superoxide intermediates. The co-deposition of mesoporous mSiO₂ and Li₂O₂ also effectively accelerated the decomposition of the discharge product by promoting the mass transfer at the cathode. This investigation of suppressing side reactions using non-aqueous electrolytes will shed a new light on the design and development of novel lithium metal batteries.