Coral-like porous microspheres comprising polydopamine-derived N-doped C-coated MoSe2 nanosheets composited with graphitic carbon as anodes for high-rate sodium- and potassium-ion batteries

We introduce highly conductive and 3D-porous coral-like microspheres comprising polydopamine-derived N-doped C-coated MoSe2 composited with graphitic carbon for the first time using a scalable spray pyrolysis process. The design strategy of the unique nanostructure effectively improves the structural robustness of electrode and enables exceptional electrochemical performances including high capacities of the cells at ultra high current rates for both sodium- and potassium-ion batteries. [Display omitted] •Synthetic strategy for 3D-porous coral-like microspheres constituted of few-layered MoSe2.•Unique structural design of anodes for both sodium- and potassium-ion batteries.•MoSe2 composited with graphitic carbon is additionally coated with N-doped carbon.•Structure with primary and secondary conductive pathways for facile electron transport. Here, an innovative strategy for the synthesis of coral-like porous microspheres comprising polydopamine-derived N-doped C-coated MoSe2 composited with graphitic carbon (Coral MoSe2-GC@NC) for use as advanced anode materials for sodium- and potassium-ion batteries (SIBs and PIBs) is introduced. The prepared composite is comprised of few-layered MoSe2 particles with enlarged interlayer spacing, which are encapsulated within the graphitic carbon matrix, which acts as an efficient transport pathway for electrons. It is also characterized by the 3D interconnected pores derived from decomposition of polystyrene nanobeads, which ensure high contact area between the electrode and electrolyte and shortened sodium- and potassium-ion diffusion length. N-doped C with high electrical conductivity is coated uniformly on the surface, which plays the role of reinforcing the structural integrity as well as providing additional conductive pathway for facile electron transport. When applied as anodes for both SIBs and PIBs, the microspheres show good structural robustness and high rate capability. The anode exhibits high structural integrity, where stable cycle performance up to 200 cycles at 2.0 A/g for SIBs and 150 cycles at 1.0 A/g for PIBs was observed. In terms of rate performance, the anode exhibited high discharge capacities of 82 mA h g−1 (at 25 A/g, SIBs) and 152 mA h g−1 (at 10 A/g, PIBs), which clearly demonstrates the structural merits of the prepared microspheres.