Sodium manganese oxides,NaxMnO2+δ(x = 0.4,0.5,0.6,0.7,1.0;δ = 0-0.3),were synthesized by solid-state reaction routine combined with sol-gel process.The structure,morphology and electrochemical performances of as-pre...Sodium manganese oxides,NaxMnO2+δ(x = 0.4,0.5,0.6,0.7,1.0;δ = 0-0.3),were synthesized by solid-state reaction routine combined with sol-gel process.The structure,morphology and electrochemical performances of as-prepared samples were characterized by XRD,SEM,CV,EIS and galvanostatic charge/discharge experiments.It is found that Na0.6MnO2+δ and Na0.7MnO2+δ have high discharge capacity and good cycle performance.At a current density of 25 mA/g at the cutoff voltage of 2.0-4.3 V,Na0.6MnO2+δ gives the second discharge capacity of 188 mA·h/g and remains 77.9% of second discharge capacity after 40 cycles.Na0.7MnO2+δ exhibits the second discharge capacity of 176 mA·h/g and shows better cyclic stability;the capacity retention after 40 cycles is close to 85.5%.Even when the current density increases to 250 mA/g,the discharge capacity of Na0.7MnO2+δ still approaches to 107 mA·h/g after 40 cycles.展开更多
基金Project(20871101) supported by the National Natural Science Foundation of ChinaProject(08A067) supported by Research Foundation of Education Bureau of Hunan Province,China
文摘Sodium manganese oxides,NaxMnO2+δ(x = 0.4,0.5,0.6,0.7,1.0;δ = 0-0.3),were synthesized by solid-state reaction routine combined with sol-gel process.The structure,morphology and electrochemical performances of as-prepared samples were characterized by XRD,SEM,CV,EIS and galvanostatic charge/discharge experiments.It is found that Na0.6MnO2+δ and Na0.7MnO2+δ have high discharge capacity and good cycle performance.At a current density of 25 mA/g at the cutoff voltage of 2.0-4.3 V,Na0.6MnO2+δ gives the second discharge capacity of 188 mA·h/g and remains 77.9% of second discharge capacity after 40 cycles.Na0.7MnO2+δ exhibits the second discharge capacity of 176 mA·h/g and shows better cyclic stability;the capacity retention after 40 cycles is close to 85.5%.Even when the current density increases to 250 mA/g,the discharge capacity of Na0.7MnO2+δ still approaches to 107 mA·h/g after 40 cycles.
