In situ construction of carbon nano-interconnects between the LiFePO4 grains using ultra low-cost asphalt

LiFePO4/C composite cathode materials with carbon nano-interconnect structures were synthesized by one-step solid state reaction using low-cost asphalt as both carbon source and reducing agent. Based on the thermogravimetry, differential scanning calorimetry, transmission electron microscopy and high-resolution transmission electron microscopy, a growth model was proposed to illustrate the formation of the carbon nano-interconnect between the LiFePO4 grains. The LiFePO4/C composite shows enhanced discharge capacity (150 mAh g(-1)) with excellent capacity retention compared with the bare LiFePO4 (41 mAh g(-1)) due to the electronically conductive nanoscale networking provided by the asphalt-based carbon. The results prove that the asphalt is a perfect carbon source and reduction agent for cost-effective production of high performance LiFePO4/C composite. (C) 2009 Elsevier Ltd. All rights reserved.