Strontium doped lanthanum manganite (LSM) effects on electrochemical performance of LSM/MnO₂ composites for supercapacitor

Sr-doped LaMnO₃ (LSM)/MnO₂ composites show different electrochemical performance and thus indicate that LSM has a positive effect on the capacitance of MnO₂ electrode. A typical LSM(10 wt%)/MnO₂ electrode presents a higher capacitance of 287.8 F g⁻¹ in 1.0 M Na₂SO₄ aqueous solution, comparing to the pristine MnO₂ electrode, 251.7 F g⁻¹. More interesting, LSM can evidently improve the capacitance of MnO₂ electrode under the high rate discharging condition. Compared with the pristine MnO₂, LSM(10 wt%)/MnO₂ 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/MnO₂ composite electrode also exhibits excellent cycle performance even after 1000 cycles. These characteristics suggest that LSM/MnO₂ composites are promising electrode materials for supercapacitor with high performance.