Nanowires embedded porous TiO2@C nanocomposite anodes for enhanced stable lithium and sodium ion battery performance.

A porous carbon nanocomposite with embedded TiO 2 nanowires (NWs) was synthesized using a two-step synthetic method in which carbon matrix was obtained by carbonizing a vacuum dried gel. This unique structure in which TiO 2 nanowires uniformly distributed in and tightly bonded to the carbon matrix shortened the electron transport path and reduced the transmission resistance. Nanoporous structure ensured continuous transfer of Li+/Na+ and supplied a large specific surface area of 280.82 m2 g−1 to provide more active sites. Different from other existing works on TiO 2 @C anode materials with TiO 2 loading higher than 60 wt%, the obtained very small amount of TiO 2 (~12 wt%) improved the electrochemical and long-cycle performance of carbon substrate with TiO 2 NWs embedded significantly, due to uniformly distributed TiO 2 NWs throughout the carbon matrix. These TiO 2 @C composite anodes could deliver a specific capacity of 286 mA h g−1 at 0.3 C, 197 mA h g−1 at 0.15 C for lithium and sodium ion batteries, respectively. It maintained remarkably stable reversible capacities of 128 and 125 mA h g−1 for lithium and sodium ion batteries at 3 C during 2500 cycles, respectively. Smaller fluctuations and smoother curves demonstrated that sodium ion storage was more stable than lithium ion storage for the TiO 2 @C composite anode. In addition, the capacitive contributions of TiO 2 @C in both systems are quantified by kinetics analysis. [ABSTRACT FROM AUTHOR]