Nitrogen Rich Carbon Coated TiO2 Nanoparticles as Anode for High Performance Lithium-ion Battery

Nitrogen-rich carbon nanosheets (CNS) wrapped anatase TiO2 (TiO2@CNS, TCNS) nanospheres are reported by a robust and facile self-assembly approach involving titanium alkoxide and CNS nanosheets under hydrothermal conditions followed by heat treatment. Optimized TCNS composite delivers superior Li storage, cycle life, and rate performance due to the synergistic effect in enhancing electronic and ionic conductivities, structural flexibility, and mechanical stability of the electrode. The TCNS nanostructures with mass loading of TiO2/CNS = 1.2 displays very high Li+ ion storage capacity (303 mAh.g─1 at 0.1C after 125 cycles) and impressive rate capability (136 mAh.g−1 at 5C after 500 cycles) with high coloumbic efficiency (99%). Detailed kinetic studies by cyclic voltammetry (CV) data revealed that TCNS nanocomposites have dual charge storage contributions arising from diffusive lithium intercalation/deintercalation characteristic of TiO2 and pseudocapacitive lithium storage (non-diffusion) from the CNS nanosheets. The high rate and superior lithium storage of TCNS core-shell nanocomposites are attributed to the significant pseudocapacitive lithium storage originated from interfaces, surface and grain boundaries. The present investigation on core-shell nanostructures using a metal oxide and 2D nanosheets could serve as an interesting strategy to tune the properties of materials for variety of applications including electrocatalysis, energy conversion/storage and photocatalysis.