Two-Dimensional Interface Engineering of Mesoporous Polydopamine on Graphene for Novel Organic Cathodes

Organic cathodes have attracted considerable attention for green and high-performance lithium-ion batteries (LIBs). Mesoporous materials are promising electrodes and their performance is governed by pore structures and sizes. This arouses the interest in the fabrication of mesoporous organic cathodes with various pore structures, as well as in the study on "structure-property" relationship to optimize the battery performance. Here, we demonstrate an interface engineering strategy for coating redox-active porous polymers, e.g. mesoporous polydopamine (mPDA), on reduced graphene oxide (rGO) nanosheets through block copolymer self assembly in solution. The interfacial self-assembly leads to the generation of two-dimensional (2D) mPDA/rGO nanocomposites with rGO nanosheets sandwiched by two mPDA layers with tunable spherical and cylindrical pore structures. As a novel organic cathode for LIBs, the mPDA/rGO nanosheets with spherical pores of a mean diameter of 8 nm exhibit a high specific capacity of 151 mA h g(-1) at 50 mA g(-1), as well as good rate performance and cycling stability with 89% retention of the initial capacity after charge-discharge for 1000 cycles. The 2D interfacial engineering protocol opens a new pathway toward 2D mesoporous polymer-based nanomaterials for energy storage devices.