Core-shell structured 1,4-benzoquinone@TiO2 cathode for lithium batteries

Organic carbonyl compounds are considered as promising candidates for lithium batteries due to their high capacity and environmental friendliness. However, they suffer from serious dissolution in the electrolyte, leading to fast capacity decay. Here we report core-shell structured 1,4-benzoquinone@titanium dioxide (BQ@TiO 2 ) composite as cathode for lithium batteries. The composite cathode can deliver a high discharge capacity of 441.2 mA h/g at 50 mA/g and a high capacity retention of 80.7% after 100 cycles. The good cycling performance of BQ@TiO 2 composite can be attributed to the suppressed dissolution of BQ, which results from the physical confinement effect of TiO 2 shell and the strong interactions between BQ and TiO 2 . Moreover, the combination of ex situ infrared spectra and density functional theory calculations reveals that the active redox sites of BQ are carbonyl groups. This work provides an alternative way to mitigate the dissolution of small carbonyl compounds and thus enhance their cycling stability.