Electrocatalysis driven high energy density Li-ion polysulfide battery

Abstract

Though carbon-based porous materials have improved lithium-sulfur (Li-S) battery performance remarkably, the poor adsorption of polysulfides and their sluggish reaction kinetics limits them from practical application. On the other hand, the presence of lithium metal especially under the highly reactive polysulfide environment causes safety concerns. Herein, we use electrocatalytically active cathode and metallic lithium-free anode to construct Li-ion polysulfide battery with enhanced reversibility and safety. Stabilizing lithium polysulfides and enhancing the reaction kinetics with minimal polarization using platinum/graphene composite holds the key to obtaining better performance, which is realized against conventional metallic lithium as well as pre-lithiated porous silicon electrodes. The electrocatalyst containing cathode composites are comparable with graphene-based electrodes regarding enhanced specific capacity retention and better reversibility in charge/discharge behavior. Furthermore, metallic lithium-free polysulfide batteries displayed exceptional performance with an energy density of 450 Wh kg−1 considering the weight of both the electroactive materials and a capacity retention of about 70% for 240 charge-discharge cycles.