Robust hetero-MoO3/MoO2@N-doped carbon nanobelts decorated with oxygen deficiencies as high-performance anodes for potassium/sodium storage

Abstract

Hetero-MoO3/MoO2@N-doped carbon nanobelt anodes (h-MoO3/MoO2@NC) with long lifespan and superior rate capability were proposed by a simple in situ reduction tactic, in which pristine MoO3 was transformed into heterogeneous MoO3/MoO2. The hetero-MoO3/MoO2 architecture significantly improves the electronic conductivity and affords abundant oxygen deficiencies. Meanwhile, the synergistic effect of internal MoO3/MoO2 heterostructure and outer N-doped carbon layer (NC) accomplishes a balance of sustainable potassium/sodium storage and ultra-durable structure stability. In potassium ion batteries, the anodes steadily maintain a reversible capacity of 283 mAh g−1 after 6000 cycles at 0.5 A g−1 and 153 mAh g−1 after 1000 cycles under 2 A g−1, as well as an impressive rate capability of 131 mAh g−1 at 3 A g−1. In sodium ion batteries, the anodes purchase a steady capacity of 152 mAh g−1 even after 10,000 cycles at 2 A g−1, and 190 mAh g−1 after 5000 cycles at 0.5 A g−1. Moreover, the h-MoO3/MoO2@NC composite possesses a prominent pseudocapacitive effect and good thermal adaptability (−10 to 50 °C) in both KIBs and SIBs. The results indicate that the h-MoO3/MoO2@NC composite would be an auspicious material for potassium/sodium storage and other ion batteries.