A General Multi-Interface Strategy toward Densified Carbon Materials with Enhanced Comprehensive Electrochemical Performance for Li/Na-Ion Batteries.

Fast charging rate and large energy storage are key requirements for lithium-ion batteries (LIBs) in electric vehicles. Developing electrode materials with high volumetric and gravimetric capacity that could be operated at a high rate is the most challenging problem. In this work, a general multi-interface strategy toward densified carbon materials with enhanced comprehensive electrochemical performance for Li/Na-ion batteries is proposed. The mixture of graphene oxide and sucrose solution is sprayed into a water/oil system and furtherly carbonized to get graphene/hard carbon spheres (GHSs). In this material, abundant ingenious internal interfaces between the crystalline graphene and the carbon matrix are created inside the hard carbon spheres. The constructed interfaces can not only work as a pathway for the escape of volatile gas generated during sucrose pyrolysis to prevent the formation of abundant pores, which leads high packing density of 0.910 g cm-3 and low surface area of 13.3 m2  g-1 , but can also provide a conductive "highway" for ions and electrons. When used as the anode material for both LIBs and sodium-ion batteries (SIBs), the GHS shows the high gravimetric/volumetric reversible capacities, high-rate performance, and low temperature properties simultaneously, implying the great potential application in practical LIBs and SIBs.