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

Abstract

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.