Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi(2)S(4)) nanoparticles hybrid anode for high performance lithium ion capacitor

Lithium ion capacitors possess an ability to bridge the gap between lithium ion battery and supercapacitor. The main concern of fabricating lithium ion capacitors is poor rate capability and cyclic stability of the anode material which uses sluggish faradaic reactions to store an electric charge. Herein, we have fabricated high performance hybrid anode material based on carbon nanofibers (CNFs) and cobalt-nickel sulfide (CoNi(2)S(4)) nanoparticles via simple electrospinning and electrodeposition methods. Porous and high conducting CNF@CoNi(2)S(4) electrode acts as an expressway network for electronic and ionic diffusion during charging-discharging processes. The effect of anode to cathode mass ratio on the performance has been studied by fabricating lithium ion capacitors with different mass ratios. The surface controlled contribution of CNF@CoNi(2)S(4) electrode was 73% which demonstrates its excellent rate capability. Lithium ion capacitor fabricated with CNF@CoNi(2)S(4) to AC mass ratio of 1:2.6 showed excellent energy density of 85.4 Wh kg(−1) with the power density of 150 W kg(−1). Also, even at the high power density of 15 kW kg(−1), the cell provided the energy density of 35 Wh kg(−1). This work offers a new strategy for designing high-performance hybrid anode with the combination of simple and cost effective approaches.