Porous carbon nanofiber webs derived from bacterial cellulose as an anode for high performance lithium ion batteries

Abstract

Carbon nanofiber webs with a hierarchically porous structure and a large surface area were developed by KOH activation of the pyrolyzed bacterial cellulose (denoted as pBC), which was extracted from the low-cost, eco-friendly and industrially producible coconut juice. The activated-pBC (denoted as A-pBC-x, x represents the mass ratio of KOH to pBC, x=5, 6 and 7) is composed of inter-welded homogeneous carbon nanofibers, which construct a mechanically robust three-dimensional (3D) conductive porous network. As an anode material for the lithium ion batteries (LIBs), the A-pBC-x exhibits significantly improved electrochemical performance compared to the pBC and current commercial graphite. Remarkably, the A-pBC-6 electrode can deliver a specific capacity of over 857.6mAhg−1 after 100 cycles at 100mAg−1 and retain high capacity of 325.38mAhg−1 even cycled at high current density of 4000mAg−1. The significant improvement for the lithium storage performance of the A-pBC-6 sample could be attributed to its hierarchical micropore–mesopore structure and high surface area, which can greatly enhance the contact area of the electrode–electrolyte, decrease the diffusion resistance of lithium ions, shorten the diffusion length of lithium ions and provide a solid and continuous pathway for electron transport.