High capacity Mo7S8 nanosheets with electrodeposited alpha-Co(OH)2 thin layer as positive electrode in hybrid potassium dual-ion supercapacitors
[ 1 ] Faculty of Chemical Technology, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland | [ 2 ] Instytut Chemii i Elektrochemii Technicznej, Wydział Technologii Chemicznej, Politechnika Poznańska | [ SzD ] doctoral school student | [ P ] employee
2023
scientific article
english
- Potassium dual-ion supercapacitors
- Alalpha-Co(OH)2@Mo7S8 nanocomposite
- Electrodeposition
- Storage mechanism
- Specific energy
EN Alpha-Co(OH)2 nanoflakes are grown on Mo7S8 electrodes by galvanostatic electrodeposition. The influence of various electrodeposition time durations on the electrochemical properties of alpha-Co(OH)2@Mo7S8 electrodes is compared. When the optimized deposition time is 1440 s, alpha-Co(OH)2@Mo7S8 composite electrode obtains the highest specific capacity of 484.8 C g−1, the lowest internal resistance of 1.96 Ω, the shortest time constant of 2.15 s, and the maximum diffusion coefficient of 2.27 × 10−14 cm2 s−1. The kinetic analysis of this electrode reveals the highest diffusion and the lowest non-diffusion contributions of 76.25% and 23.75% at 0.5 mV s−1, respectively. Ex-situ X-ray photoelectron spectroscopy shows that chemical valences of Mo and Co increased from +2 to +4 and from +2 to +3 after OH− insertion, respectively. The hybrid potassium dual-ion supercapacitor is assembled with alpha-Co(OH)2@Mo7S8 cathode (positive electrode) and molybdenum-phosphate-based MoPO@Mo7S8 anode (negative electrode). The device exhibits remarkable capacitance characteristics with a high specific energy of 59.4 Wh kg−1 at a specific power of 734 W kg−1 and a capacity-maintaining retention rate of 97.3% after 10,000 charge–discharge cycles.
24.04.2024
142467-1 - 142467-12
Article number: 142467
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