In situ sol–gel synthesis of Ti₂Nb₁₀O₂₉/C nanoparticles with enhanced pseudocapacitive contribution for a high-rate lithium-ion battery

Ti₂Nb₁₀O₂₉/C nanoparticles with a carbon content of 13 wt% and a mean size of 50 nm were fabricated through a convenient and effective in situ sol–gel process. The small grain size and carbon modification can improve the pseudocapacitive effect of the Ti₂Nb₁₀O₂₉/C nanoparticles, leading to excellent rate capacity, especially at high current rate. Specifically, the discharge capacity of the Ti₂Nb₁₀O₂₉/C electrode is 258.3, 236.0, 216.6, 184.5 and 161.5 mAh·g⁻¹ at different current densities of 1C, 5C, 10C, 20C and 30C. Nevertheless, the discharge capacity of the Ti₂Nb₁₀O₂₉ electrode is 244.9 mAh·g⁻¹ at 1C, which is rapidly reduced to 89.7 mAh·g⁻¹ at 30C. In addition, the small size and carbon layer of the Ti₂Nb₁₀O₂₉/C nanoparticles can supply abundant active sites for Li⁺ storage as well as enhance the electronic conductivity and Li⁺ diffusion, endowing these nanoparticles with a high discharge capacity and excellent cycle performance.