Mesoporous TiO₂ nanosheets anchored on graphene for ultra long life Na-ion batteries

Sodium-ion batteries, which have a similar electrochemical reaction mechanism to lithium-ion batteries, have been considered as one of the most potential lithium-ion battery alternatives due to the rich reserves of sodium. However, it is very hard to find appropriate electrode materials imputing the large radius of sodium-ion. TiO₂ is particularly interesting as anodes for sodium-ion batteries due to their reasonable operation voltage, cost, and nontoxicity. To obtain a better electrochemical property, mesoporous TiO₂ nanosheets (NSs)/reduced graphene oxide (rGO) composites have been synthesized via a scalable hydrothermal-solvothermal method with a subsequent calcination process. Benefitting from unique structure design, TiO₂ NSs@rGO exhibits a superior cycle stability (90 mAh g^-1 after 10 000 cycles at a high current rate of 20 C) and satisfactory rate performance (97.3 mAh g^-1 at 25 C). To our knowledge, such ultra long cycle life has not previously been reported.