Hierarchical MoS2/m-C@a-C@Ti3C2 nanohybrids as superior electrodes for enhanced sodium storage and hydrogen evolution reaction

Abstract Development of sodium-ion batteries (SIBs) and hydrogen evolution reaction (HER) technologies to achieve electrochemical energy storage and conversion has attracted intensive interest. MoS2 is bifunctionally active towards both SIBs and HER. However, poor electrical conductivity, limited active sites and sluggish ion diffusion kinetics generally give rise to rapid capacity fading, poor cycling stability, and low electrocatalytic activity when used as electrode materials. Herein we designed hierarchical MoS2/m-C@a-C@Ti3C2 nanohybrids as electrode materials for SIBs and HER. The nanohybrids are fabricated by vertically anchoring the few-atomic-layered MoS2 nanosheets, with alternated intercalation of carbon monolayers, on the both sides of carbon-stabilized Ti3C2 substrate. They afford 3D interconnected conductive networks, expanded interlayer distance and strong interfacial coupling, enabling fast charge transfer, abundant active sites, high structural stability and ion diffusion kinetics. Benefited from the synergistic effects, the nanohybrids exhibit ultra-long cycling life of 2000 cycles with high capacities and slow capacity loss per cycle at 2 and 5 A g-1 for Na+ storage. They also present high HER activity in both alkaline and acidic solutions (overpotential: 110 and 93 mV (vs. RHE) at 10 mA cm-2). These superior properties demonstrate the great promise of this designed strategy for energy storage and conversion.