摘要
Sodium metal is a promising anode for sodium batteries due to its high theoretical capacity and low cost.However,the serious Na dendrite growth and low Coulombic efficiency,especially at high current densities/cycling capacities,severely limit the application of sodium metal anodes.Herein,trifluoromethylfullerene,C_(60)(CF_(3))_(6),is designed as an electrolyte additive to enable the high-rate cycling of sodium metal anodes with high Coulombic efficiency.The CF3 groups contribute to the formation of stable NaF-rich solid electrolyte interface layer,while C_(60)cages induce the uniform distribution of sodium ions and promote the formation of smooth and compact morphology.Thus,Na||Cu cell with C_(60)(CF_(3))_(6)can be cycled at 2 mA·cm^(−2)and 10 mAh·cm^(−2)over 180 cycles with an average Coulombic efficiency of 99.9%,and Na||Na cell can be cycled at 10 mA·cm^(−2)over 600 cycles.Furthermore,Na||NaV2(PO_(4))_(3)@C full cell exhibits high capacity retention of 84%over 2,000 cycles at 20 C(~3 mA·cm^(−2)).
基金
the National Science Foundation of China(Nos.21925104,51672093,51821005,U1966214,51902116,and 21975087)。
