Thermodynamic anti-agglomeration based selenium-doped tin oxide network: Enhancing cycling stability of high-rate lithium storage

In this work, the grain line-cutting effect induced by selenium doping into SnO2 aggregation was proposed to prepare uniformly distributed SnO2/Se nanoparticles (SnO2/Se NPs) network with thermodynamic anti-agglomeration force during high-temperature sintering. These SnO2/Se NPs offers abundant active sites, reduced volume expansion and fast Li+ diffusion ability, especially the enhanced electronic conductivity due to oxygen vacancies introduced by doping. More importantly, the thermodynamic anti-agglomeration of SnO2/Se NPs effectively suppresses the Sn coarsening and Li2O/Sn phase segregation during repeated charge/discharge processes. Consequently, the SnO2/Se NPs anode delivers excellent reversible capacity of 515 mAh g−1 after 500 cycles at 1 A g−1, and the SnO2/Se NPs||LiFePO4 full cells maintains a high-rate capacity of 109 mAh g−1 at 0.3 A g−1. The SnO2/Se NPs anode is compatible with high concentration polymer electrolyte (HCPE), which shows a capacity of 520 mAh g−1 after 100 cycles at 0.2 A g−1 in solid state batteries. This study provides a new insight for improving the cyclic stability of conversion-alloying anodes, offering their promising prospects for the full batteries and solid-state batteries.