Hierarchical mesoporous MoSe2@CoSe/N-doped carbon nanocomposite for sodium ion batteries and hydrogen evolution reaction applications

MoSe2 has been attracting numerous attentions for energy storage and conversion applications due to its unique characteristics. However, the intrinsic low electric conductivity and sluggish reaction kinetics hinder its electrochemical performance. Herein, hierarchical mesoporous MoSe2@CoSe/N-doped carbon (N-C) composite was in situ fabricated from MoO3@Co-MOF precursor in selenium atmosphere. The incorporation of CoSe and N-C greatly enhanced the reaction kinetics and electronic conductivity of the composite. Moreover, the hierarchical mesoporous structure ensures fast Na+ diffusion and excellent structural stability upon cycling. As expected, the optimally structured composite showed superior electrochemical performance as an anode material in sodium-ion batteries, including a high specific capacity of 485 mA h g(-1) at 0.1 A g(-1) and good rate capability that it retains 91.4% of its 398 mA h g(-1) initial capacity after 300 cycles at 2 A g(-1). When paired with Na3V2(PO4)(3)/C, it also delivers a high reversible capacity of 345 mA h g(-1) in full-cell configuration. In addition, as a catalyst, it also exhibits outstanding HER activity with a small overpotential of 64 mV and a Tafel slope of 53 mV dec(-1).