Microbundles of carbon nanostructures as binder free highly conductive matrix for LiFePO4 battery cathode

Microbundles of carbon nanostructures (CNS) have been used to fabricate binder-free LiFePO4 electrodes. The inherent ability of CNS to form a nano-porous structure after the reassembly of CNS dispersion from solution to film-forming state is used to encapsulate the LiFePO4 particles. The LiFePO4/CNS electrode shows high electrical conductivity of 9.1 S cm(-1) compared to 0.4 S cm(-1) for conventional LiFePO4/carbon electrodes. LiFePO4/CNS flexible electrodes shows specific discharge capacity of 56 mAh g(-1), 41 mAh g(-1) and 37 mAh g(-1) at 1C, 3C and 5C rates respectively. These specific discharge capacities are higher than that of conventional LiFePO4/carbon electrodes i.e. 40 mAh g(-1), 13 mAh g(-1) and 0.01 mAh g(-1) at 1C, 3C and 5C rates respectively. Improvements in the specific discharge capacity at high C-rate is attributed to highly conductive pathways between the CNS and LiFePO4 particles, which assist fast transport of electrons at the electrode/CNS interfaces and between the electrode particles for rapid electrochemical reactions. (C) 2014 Elsevier B.V. All rights reserved.