V5S8 nanoparticles anchored on carbon nanofibers for fast and durable sodium and potassium ion storage

Abstract

Sodium- and potassium-ion batteries (SIBs and PIBs), as the next-generation batteries, attract a lot of attention due to the abundance and even distribution of sodium and potassium sources. However, both SIBs and PIBs need high-performing active anode materials to widen their industrial applications. Transition metal sulfides, possessing high theoretical capacity, show promise for SIB and PIB anodes. However, the structural instability of these sulfides occurring due to the volume changes during the active ion insertion and release limits their applications. In this work, V5S8 nanoparticles anchored on carbon nanofibers (V5S8@CNF) were fabricated for SIB and PIB anodes. The SIB cells exhibited outstanding performance with 351.0 mA h g−1 specific capacity after 400 cycles at 0.2 A g−1. A similar PIB cell demonstrated 289.2 mA h g−1 specific capacity after 200 cycles at 0.1 A g−1. Long-term stability of SIBs and PIBs for 10,000 and 2000 cycles at 2 and 1 A g−1, respectively, showed very stable specific capacities equal to 251.0 and 190.1 mA h g−1. The outstanding energy-storage-related properties of the sulfide-based anodes provide insights into techniques for improving Na+ and K+ electrochemical reactions assisted by two-dimensional layered transition metal sulfides.