Enhanced electrochemical performance of lithium-sulfur batteries using a V2O5/graphene interlayer

Abstract

• The V 2 O 5 /G layer is prepared as vice-electrode to enhance the performance of Li-S batteries. • The conductive interlayer can expand the electrode area and restrain the shuttle effect. • V 2 O 5 acts as an active material to contribute extra cathode capacity to the batteries. To improve the electrochemical performance of lithium-sulfur (Li-S) batteries, we develop a new strategy to construct the V 2 O 5 yolk-shell microspheres/graphene nanosheets (V 2 O 5 /G) layer on commercial polypropylene (PP) separator as a vice-electrode. On one hand, the V 2 O 5 /G interlayer can act as a barrier to block polysulfides diffusion and then suppress the troublesome shuttle effect. On the other hand, lithium ions can insert in and extract from V 2 O 5 during discharge/charge processes, and thus contribute extra cathode capacity and large voltage window to the batteries. As expected, the Li-S batteries with a V 2 O 5 /G interlayer deliver a large voltage window of 2.0 V (3.6–1.6 V) and a significantly improved electrochemical performance. The work provides a new idea for the design of the high-performance Li-S battery.