Laser induced molybdenum sulphide loading on doped graphene cathode for highly stable lithium sulphur battery

Abstract

Lithium sulphur (Li-S) batteries are known to have much higher charge capacity than the currently widely used lithium-ion batteries with graphite anodes. However, maintaining high charge cycle stability is a key challenge for Li-S batteries due to the shuttle effect. Here we show highly stable characteristics with 100% charge capacity of Li-S batteries with 500 charge/discharge cycles at 0.5 C, 1 C, 2 C and 3 C charge rates. This was made possible by the combination of laser synthesised sulfur (S) and nitrogen (N) doped graphene electrodes (without a binder) with molybdenum sulphide (MoS2) nanoparticle loading. The N/S doped porous graphene structure presented enhanced interface adsorption by the production of –SO2, which suppressed diffusion of polysulfide into the electrolyte through promoting oxygen-containing functional groups chemically bonding with sulfur. A low electrolyte resistance, interphase contact resistance and charge-transfer resistance accelerate electrons and Li+ transport by laser induced N/S doped graphene.