Two-dimentional MoSe2/chitosan-derived nitrogen-doped carbon composite enabling stable sodium/potassium storage

The large ionic size of Na+ and K+ leads to severe volume variation and sluggish reaction kinetics, hindering the cycle stability and specific capacity of sodium/potassium-ion batteries (SIBs/PIBs). It is of great importance to develop high-performance anodes for SIBs/PIBs with superior stability, high capacity, and low cost. Herein, we elaborately designed MoSe2 encapsulated in biomass-derived nitrogen (N)-doped carbon (MoSe2/N–C) composite, where chitosan acts as an adsorbent and carbon precursor. In the composite, the ultra-thin MoSe2 nanosheets compose of (size of ca. 10 nm) nanocrystals embed on the chitosan derived N-doped carbon. The resultant MoSe2/N–C electrode exhibits admirable electrochemical performance for SIBs and PIBs. It displays a Na storage capacity of 505 mAh g−1 at 0.1 A g−1 for 100 cycles. More importantly, the composite anode also exhibits impressive long-term cycling performance, which retains 266 mAh g−1 at 1 A g−1 over 1200 cycles. When employed as an anode of PIBs, it also displays an impressive storage capacity of 240 mAh g−1 at 0.1 A g−1 after 100 cycles. This finding is expected to be of immediate benefit to researchers in using biomass to fabricate energy storage applications.