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, heterostructure of SnO2 encapsulated amorphous Nb2O5 is spontaneously synthesized. Insertion-type anode outer shell, playing as reaction containers and fast ionic pathways, physically inhibits the Sn atoms’ migration enhances kinetics. Moreover, strong chemical interactions are found at SnO2/Nb2O5 interfaces, which ensure solid encapsulation cores even after 500 cycles. When used lithium-ion batteries, this heterostructured exhibits high cycling stability capacity 626 mA h g−1 1000 cycles 2 A (85% retention) good rate performance 340 8 g−1.