Dual engineering of hetero-interfaces and architecture in MoSe2/VSe1.6@NC nanoflower for fast and stable sodium/potassium storage

Abstract

Rational structure design is significant for the selenide anodes in the sodium/potassium ion batteries (SIBs/PIBs). Herein, dual engineering of hetero-interfaces and architecture is proposed to design SIB/PIB anodes. Attributed to the coordination binding with Mo₇O₂₄^6- and VO₃^-, the polydopamine assembly is demonstrated as an ideal template to produce bimetallic selenide of MoSe₂/VSe_1.6 anchoring on the in-situ N-doped carbon matrix (MoSe₂/VSe_1.6@NC). This ingenious hierarchical nanoflower structure can shorten the Na⁺/K⁺ diffusion length, increase the electron conductivity and buffer the volume changes, which can promote Na⁺/K⁺ reaction kinetics and stabilize the cycling performance. Consequently, the sodium/ potassium storage performance of MoSe₂/VSe_1.6@NC can be boosted. In SIBs, it achieves a capacity of 202 mAh/g at 10.0 A/g for 5000 cycles. Meanwhile, stable capacities of 207.1 mAh/g can be reached at 1.0 A/g over 1000 cycles in the PIBs. Furthermore, impressive capacities of 222.1 mAh/g and 100.4 mAh/g are delivered in the full cells of MoSe₂/VSe_1.6@NC//Na₃V₂(PO4)₃@C and MoSe₂/VSe_1.6@NC//FePBA, respectively. This proves the potential practical application for the MoSe₂/VSe_1.6@NC anode in SIBs/PIBs.

Keywords: Bimetallic selenide; Hetero-interfaces; High-rate; Sodium/potassium storage; Ultra-long stability.