Metal organic frameworks derived porous lithium iron phosphate with continuous nitrogen-doped carbon networks for lithium ion batteries

摘要

Lithium iron phosphate (LiFePO4) nanoparticles embedded in the continuous interconnected nitrogen doped carbon networks (LFP/N-CNWs) is an optimal architecture to fast electron and Li+ conduction. This paper, for the first time, reports a reasonable design and successful preparation of porous hierarchical LFP/N-CNWs composites using unique Fe-based metal organic framework (MIL-100(Fe)) as both template and starting material of Fe and C. Such nitrogen-doped carbon networks (N-CNWs) surrounding the lithium iron phosphate nanoparticles facilitate the transfer of Li+ and electrons throughout the electrodes, which significantly decreases the internal resistance for the electrodes and results in the efficient utilization of LiFePO4. The synthesized LFP/N-CNWs composites possess a porous structure with an amazing surface area of 129 m(2) g(-1), considerably enhanced electrical conductivities of 7.58 x 10(-2) S cm(-1) and Li+ diffusion coefficient of 8.82 x 10(-14) cm(-2) s(-1), thereby delivering excellent discharge capacities of 161.5 and 93.6 mAh.g(-1) at 0.1C and 20C, respectively. (C) 2015 Elsevier B.V. All rights reserved.