MOF composite fibrous separators for high-rate lithium-ion batteries

Abstract

In this study, metal-organic frameworks (MOF)/polyacrylonitrile (PAN) composite fibrous separators were prepared for high-rate Li-ion batteries by anchoring MOF into PAN nanofibrous network. The MOF/PAN separators possess excellent dimensional, thermal stability, intrinsically high porosity, and good electrolyte adsorption, which contribute excellent Li-ion transport capacity. The Li/Li symmetric cells assembled with MOF/PAN separators demonstrate improved coulombic efficiency, inhibition of Li dendrites, and excellent long-term cycle stability with low-voltage hysteresis of around 46 mV after more than 1200 h Li plating/stripping process, in comparison with around 350 mV after 360 h for commercialized Celgard 2400 separator. The excellent ionic transport capacity reveals impressive performance of the LiFePO4-MOF/PAN-Li metal full cells under high rate and the capacity that could be up to 104 mAh g−1 at 5 C after 2000 cycles with a coulombic efficiency of almost 100%. This work provides a new prospect for the development of high-rate lithium-ion batteries.