Multigrain electrospun nickel doped lithium titanate nanofibers with high power lithium ion storage

Novel in situ nickel doped 1-D lithium titanate nanofibers (Li₄Ti_5-xNi_xO₁₂, where x = 0, 0.05 and 0.1) have been successfully synthesized using a facile electrospinning process. Physical characterization reveals that nickel is homogeneously incorporated into the lattice of lithium titanate nanofibers (LTONFs) which significantly improves their properties yielding outstanding electrochemical performance in a lithium ion battery at high power rates and significant reduction in the voltage gap between the oxidation and reduction peaks. A capacity of 190 mA h g^-1 has been obtained at 0.2C for the 10% nickel doped nanofibers (Ni-LTONF₁₀), which is higher than the theoretical capacity of pristine lithium titanate (175 mA h g^-1) and they also show superior rate capability resulting in 63 mA h g^-1 obtained at 50C, which is 20 times higher than that of un-doped pristine LTONFs and lithium titanate nanoparticles (LTONPs). Finally, a hybrid supercapacitor is fabricated using Ni-LTONF₁₀, showing superior energy density at high power density.