In situ thermal exclusion induced Sb and Sb-doped SnO2 nanoheterostructuring and its improvements in cycling stabilities and rate capacities for Na+ storage

Abstract

This work reports a novel in situ thermal exclusion approach for the synthesis of carbon coated Sb and Sb-doped SnO₂ hetero-nanoparticles (Sb-ATO hetero-NPs) deposited on MWCNTs (C@Sb-ATO/MWCNTs) through the annealing of PPY@ATO/MWCNTs. Depending on the specific structural features of C@Sb-ATO/MWCNTs, which integrate the advantages of nanostructuring, elemental doping, heterostructuring, and carbon integration, C@Sb-ATO/MWCNTs shows improved performance for Na⁺ storage. Specifically, it exhibits a high reversible capacity (430.6 mA h g⁻¹ at 0.1 A g⁻¹), superior rate capabilities (198.5 mA h g⁻¹ at 30.0 A g⁻¹) and remarkable cycling stabilities (275.5 mA h g⁻¹ at 5.0 A g⁻¹ for up to 10 000 cycles). The Sb doping and Sb-ATO nanoheterostructuring are demonstrated to be the main origins of the high performance of C@Sb-ATO/MWCNTs. DFT calculations indicate that the Sb doping can increase the electrical conductivity of ATO and promote the diffusion and storage of Na⁺ ions in ATO, and the electrical conductivity of the Sb-ATO hetero-NPs can be further increased by the Sb-ATO heterostructuring. The result presented here indicates that the strategy in combination of nanostructuring, elemental doping, heterostructuring, and carbon integration is a promising way to obtain anode materials with high performance for Na⁺ storage.