Highly Stable LiI/Active Graphene Composite Cathodes for Efficient Lithium-Iodine Batteries

Abstract

Lithium iodide (LiI) is regarded as a promising cathode material for lithium-iodine (Li-I2) batteries in terms of its high merits, high theoretical specific capacity of 200 mAh g–1 and good compatibility with lithium metal-free anodes. However, LiI suffers from poor cycling stability and rate capability resulted from the serious shuttle effect of iodide and its low conductivity. Herein, a commercial active graphene (AG) with high pore volume, high specific surface area and good conductivity is employed as a host material for lithium iodide (LiI). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) characterizations of the resultant LiI/AG composites indicate that LiI uniformly disperses in the nanopores of AG. The LiI/AG composite cathode with 40 wt.% LiI shows enhanced electrochemical performance including excellent cycling stability and high Coulombic efficiency. This work demonstrates a simple strategy to fabricate efficient composite cathodes for high-performance rechargeable Li-I2 batteries.