A High-Performance Alloy-Based Anode Enabled by Surface and Interface Engineering for Wide-Temperature Sodium-Ion Batteries

摘要

Alloy-based anodes have shown great potential to be applied in sodium-ionbatteries (SIBs) due to their high theoretical capacities, suitable workingpotential, and abundant earth reserves. However, their practical applicationsare severely impeded by large volume expansion, unstable solid-electrolyteinterfaces (SEI), and sluggish reaction kinetics during cycling. Herein, asurface engineering of tin nanorods via N-doped carbon layers (Sn@NC) andan interface engineering strategy to improve the electrochemical performancein SIBs are reported. In particular, the authors demonstrate that uniformsurface modification can effectively facilitate electron and sodium transportkinetics, confine alloy pulverization, and simultaneously synergizeinteractions with the ether-based electrolyte to form a robustorganic-inorganic SEI. Moreover, it is discovered that the diethylene glycoldimethyl ether electrolyte with strong stability and an optimized Na+ solvationstructure can co-embed the carbon layer to achieve fast reaction kinetics.Consequently, Sn@NC anodes deliver extra-long cycling stability of more than10 000 cycles. The full cell of Na_3V_2(PO_4)_3║Sn@NC exhibits high energydensity (215 Wh kg~(?1)), excellent high-rate capability (reaches 80 capacity in2 min), and long cycle life over a wide temperature range of ?20 to 50 ℃.