Electrochemical performance of porous TiO2 microspheres coated with nitrogen-doped carbon as an anode material for lithium-ion batteries†

TiO₂ has a robust structure and low cost and is non-toxic. However, its low electronic conductivity and lithium-ion diffusivity impede its practical application in LIBs. To improve the conductivity and lithium-ion dynamics of titanium dioxide (TiO₂), we synthesized porous TiO₂ microspheres coated with nitrogen-doped carbon (TiO₂@C–N) through a solvothermal method combined with pyrolysis and carbonization technology. The nitrogen-doped carbon coating was prepared using a one-pot sealed carbonization method with pyrrole as the source of carbon and nitrogen. The porous TiO₂ matrix in the TiO₂@C–N composites provided numerous open transport pathways and storage sites for Li ions, while the nitrogen-doped carbon coating promoted the movement of electrons, leading to enhanced electrical conductivity. Undergoing 5000 cycles at 2 A g⁻¹, the TiO₂@C–N electrode delivered a cycling capacity of 71.8 mA h g⁻¹, while the capacity of commercial graphite decayed rapidly after 3300 cycles. Rate tests of both samples under the same conditions demonstrated that the TiO₂@C–N electrode was more suitable for fast charging/discharging than the graphite anode. Therefore, the TiO₂@C–N composites are expected to be an alternative to commercial graphite anodes based on their electrochemical performance.