Controllable nitrogen doping and specific surface from freestanding TiO2@carbon nanofibers as anodes for lithium ion battery

Abstract Further modification of carbon and transition metal composites has become a hot spot in the preparation of anode materials for lithium ion battery, including various morphologies, nitrogen doping and porous introduction. However, the synergistic effect of specific surface area and nitrogen doping content of composite materials on the electrochemical performance as anode materials for lithium ion batteries has not been revealed. In this paper, the carbon nanofibers loaded with titanium dioxide are fabricated via electrospinning method followed by calcination process with simple addition admixture of diisopropyl azodiformate in precursor solution. The pores are introduced into the composite with controllable nitrogen doping and surface area simultaneously. The specific capacity of titanium dioxide @carbon nanofibers has been increased from 192.2 mAh g −1 to 336 mAh g −1 due to the increased nitrogen content of the composite from 7.18% to 10.21%, and elevated specific surface area from 67.23 to 111.15 m 2  g −1 , which can endow the composite superior conductivity and more active sites. The capacity contribution of the total specific capacity has decreased from 60.8% to 44.7% compared with original sample, proving that increasing diffusion controlled Faradaic Li-ion insertion origins from nitrogen doping.