Different proportions of C/KCu7S4 hybrid structure for high-performance supercapacitors

• KCu7S4 has the channels structure, minor resistance and good electrochemical property.
• The changed KCu7S4 electrode structure improve its electrochemical performance.
• Constructing a hybrid C/KCu7S4 for ECs. The hybrid ECs demonstrate outstanding electrochemical performance.

KCu7S4 has the channel structure and minor resistance. Its double larger channels ensure that the ions can well exchange with other's, at the same time, can shorten the ionic diffusion path and improve the ionic and electronic transport. So KCu7S4 shows good electrochemical property. The paper reports a novel and high performance supercapacitor based on hybrid carbon particles and KCu7S4 (C/KCu7S4) electrode. For the hybrid structure with different proportions of C and KCu7S4, the C/KCu7S4 (1:10) hybrid supercapacitor shows preferable electrochemical performance and large specific capacitance (469 mF cm−2) at high charge–discharge rate (2 mA), still retaining ∼95% of the capacitance over 5000 cycles by charge–discharge process at a fixed current of 10 mA. Three supercapacitor units in series can light 50 light-emitting diodes (LEDs) for 2.5 min, 10 LEDs for 4 min, one LED for 5.5 min. The much-increased capacity, rate capability, and cycling stability may be attributed to the superionic conductive KCu7S4 nanowires and C/KCu7S4 hybrid structure, which improve ionic and electronic transport, enhance the kinetics of redox reactions through the electrode system.

Three C/KCu7S4 hybrid ECs units in series to light a light-emitting diode (LED) for 5.5 min, 10 light-emitting diodes (LEDs) for 4 min, 50 light-emitting for 2.5 min. The hybrid ECs can deliver the largest specific capacitance of 469 m F cm−2 (∼300 F g−1) at the current of 2 mA, the highest energy density of 8.14 mWh cm−3 and the maximum power density of 664.4 mW cm−3 and cycling stability (95% capacity retention after 5000 cycles), possibly serving as a promising potential for the high-performance supercapacitor.Figure optionsDownload as PowerPoint slide