Superior full battery performance of tunable hollow N-Doped carbonaceous fibers encapsulating Ni₃S₂ nanocrystals with enhanced Li/Na storage

A controlled bioleaching strategy to embed Ni₃S₂ nanocrystals into 1D hollow carbonaceous fibers derived from renewable biomass was designed with enough inner voids as well as abundant natural pyridinic and pyrrolic nitrogen. The hollow fiber-based electrode can prevent the large volume expansion, improve the electronic conductivity and enhance the diffusion rate of Li⁺/Na⁺ ion. As a result, the synthesized Ni₃S₂/hollow carbonaceous fiber electrodes deliver excellent reversible capacity and outstanding cycle stability, i.e., 673.4 mAh g⁻¹ at 0.1 A g⁻¹ after 100 cycles for lithium-ion batteries (LIBs), 378.4 mAh g⁻¹ at 1 A g⁻¹ after 100 cycles for sodium-ion batteries (SIBs), in electrochemical half-cells. More importantly, a superior electrochemical performance is obtained in a full-cell when employing Na₃V₂(PO₄)₃ as cathode (i.e., 218.9 mAh g⁻¹ after 100 cycles at 0.5 A g⁻¹).