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

摘要

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 and161.5 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.