Nanoconfined nitrogen-doped carbon-coated MnO nanoparticles in graphene enabling high performance for lithium-ion batteries and oxygen reduction reaction

To tackle the issues of inferior cycling stability and low conductivity for MnO as an anode material for lithium ion batteries (LIBs) and as a catalyst for oxygen reduction reaction (ORR), a facile and effective strategy is explored to confine N-doped carbon-coated MnO nanoparticles in a conductive graphene matrix. The synthesis of the GMNCs involves the two-step coating of Mn(3)O(4) nanocrystals with polydopamine and graphene, followed by heat treatment to form the GNS@MnO@N-doped carbon composites (GMNCs). When evaluated as anode materials for LIBs, the as-prepared GMNCs exhibit an improved cycling stability (754.3 mA h g(–1) after 350 cycles at 0.1 A g(–1)) compared to carbon-coated MnO and pure Mn(3)O(4) due to the double carbon coating design. When evaluated as catalysts for ORR, the as-prepared GMNCs exhibit higher electrocatalytic activity than that of pure Mn(3)O(4) and MnO catalysts, and superior stability to a commercial Pt/C catalyst due to the synergetic effect between the MnO and N-doped double carbon coating. The optimum design of the unique nanostructures with the synergetic effect provides a new route to design advanced materials as electrode/catalysts for energy conversion and storage.