Strontium doped lanthanum manganite (LSM) effects on electrochemical performance of LSM/MnO_2 composites for supercapacitor

摘要

Sr-doped LaMnO_3 (LSM)/MnO_2 composites show different electrochemical performance and thus indicate that LSM has a positive effect on the capacitance of MnO_2 electrode. A typical LSM(10 wt%)/MnO_2 electrode presents a higher capacitance of 287.8 F g~(-1) in 1.0 M Na_2SO_4 aqueous solution, comparing to the pristine MnO_2 electrode, 251.7 F g~(-1). More interesting, LSM can evidently improve the capacitance of MnO_2 electrode under the high rate discharging condition. Compared with the pristine MnO_2, LSM(10 wt%)/MnO_2 shows excellent capacitance improvement of 11 % at low scan rate of 2 mV s~(-1), 33% at intermediate scan rate of 50 mV s~(-1) and 47.1% at a high scan rate of 200 mV s~(-1), respectively. The higher the discharge rate is, the better capacitance improvement can be obtained. Moreover, LSM/MnO_2 composite electrode also exhibits excellent cycle performance even after 1000 cycles. These characteristics suggest that LSM/ MnO_2 composites are promising electrode materials for supercapacitor with high performance.