Confined MoS2 nanosheets grown on 3D interconnected N, S co-doped carbon nanofibers as a free-standing anode for sodium-ion batteries

Abstract

Two-dimensional layer structured MoS2 anode material emerges as a prospective candidate for sodium-ion batteries (SIBs), while its poor electronic conductivity and structural degradation still induce the unsatisfying rate performance and limited cycling stability. Herein, a novel freestanding MoS2/C anode material is fabricated by growing MoS2 nanosheets with flower-like nanostructure on 3D interconnected N, S co-doped carbon nanofibers. The constructed freestanding 3D conductive matrix can efficiently promote the electron transfer and ion transport as well as ameliorate the volume variations and avoid the aggregation of the MoS2 nanosheets to maintain the structural stability. The boosting effect of N, S co-doping was further confirmed by the first-principles calculation, which can accelerate conductivity, lower the Na+ adsorption energy, introduce more heteroatomic defects and offer plentiful active sites for Na+ storage, thus enhancing the electrochemical properties. The as-prepared free-standing MoS2/N, S co-doped carbon anode exhibits excellent long cycle and high rate properties, showing higher reversible capacities of 500 mA h g−1 after 100 cycles at 0.1 A g−1, 327 mA h g−1 over 1000 cycles at 1 A g−1 and remarkable high-rate response up to 8 A g−1. The facile and effective strategy proposed in this study could be widely developed in other high-capacity anode materials for various energy storage applications.