Inter-Bonded Carbon Nanofibers Based Anode for High Areal Capacity Lithium-Ion Battery

Abstract

Improving anode electrode conductivity and boosting mechanical strength of carbon nanofibers (CNFs) is beneficial to fabricate binder-free anode for high areal capacity in Lithium-ion Batteries (LIBs). A typical way to improve CNFs conductivity is adding high conductive transition metals to CNFs precursors. In this work, several ideas are incorporated together to enhance LIB performance. First, CNFs with 3% and 5% nickel is introduced by using electrospinning technique for improving electrical conductivity and capacity, because nickel has high theoretical capacity (718mAh/g) and enhanced electrical conductivity (1.43x107 S/m). Small addition of Nickel was done because higher usage of nickel metal fillers cause volume expansion during cycling which results in poor cell performance. Second, development of strong mechanical connections, enhancement of electron transport by better inter-bonding network among the CNFs is also addressed here. In this study, polyvinylpyrrolidone (PVP)/ polyacrylonitrile (PAN) polymers are used to fabricate the CNFs where the semi-interpenetrating polymer PVP assists in creating inter-bonded morphologies in the nanofibers. Thus, well inter-bonded CNFs showed not only the better areal capacity but also the higher specific capacity. Further an optimum stabilization and carbonization heat-treatment process was also observed. The synergetic effect of adding high conductive Nickel and well-inter-bonded CNFs network represents a favorable anode material with an areal capacity as high as 792.7 μAh/cm2 after 300 cycles at a current density of 1.16 mA/cm2 and excellent cycling stability.