A Hybrid Mg2+/Li+ Battery Based on Interlayer-Expanded MoS2/Graphene Cathode

The hybrid Mg2+/Li+ battery (MLIB) is a very promising energy storage technology that combines the advantage of the Li and Mg electrochemistry. However, previous research has shown that the battery performance is limited due to the strong dependence on the Li content in the dual Mg2+/Li+ electrolyte. This limitation can be circumvented by significantly improving the diffusion kinetics of Mg2+ in the electrode, so that both Li+ and Mg2+ ions can be utilized as charge carriers. Herein, a free-standing interlayer expanded MoS2/graphene composite(E-MG) is demonstrated as a cathode for MLIB. The key advantage of this cathode is to enable the efficient intercalation of both Mg2+ and Li+. The E-MG electrode displays a reversible capacity of similar to 300 mA h g(-1) at 20 mA g(-1) in an MLIB cell, corresponding to a specific energy density up to similar to 316.9 W h kg(-1), which is comparable to that of the state-of-the-art Li-ion batteries (LIBs) and has no dendrite formation. The composite electrode is stable against cycling with a coulombic efficiency close to 100% at 500 mA g(-1). This new electrode design represents a significant step forward for building a safe and high-density electrochemical energy storage system.