Achieving highly stable Sn-based anode by a stiff encapsulation heterostructure

Rationally designed heterostructures provide attractive prospects for energy storage electrodes by combining different active materials with distinct electrochemical properties. Herein, through a phase separation strategy, a heterostructure of SnO₂ encapsulated by amorphous Nb₂O₅ is spontaneously synthesized. Insertion-type anode Nb₂O₅ outer shell, playing as reaction containers and fast ionic pathways, physically inhibits the Sn atoms’ migration and enhances the reaction kinetics. Moreover, strong chemical interactions are found at the SnO₂/Nb₂O₅ interfaces, which ensure the solid encapsulation of the SnO₂ cores even after 500 cycles. When used for lithium-ion batteries, this heterostructured anode exhibits high cycling stability with a capacity of 626 mA h g⁻¹ after 1000 cycles at 2 A g⁻¹ (85% capacity retention) and good rate performance with the capacity of 340 mA h g⁻¹ at 8 A g⁻¹.[Figure not available: see fulltext.] © 2021, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.