High-energy-density magnesium ion supercapacitors fabricated by using in situ inverse charge process
발표자
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초록
내용
Electrochemical double-layer capacitors (EDLCs) store charge by physical adsorption and desorption of electrolyte ions so that they can deliver a high power with great cycling stability. However, energy densities of them are much lower than those of rechargeable batteries, requiring a research strategy to breakthrough this long-standing issue. In this study, 4 V-class Mg-ion pseudocapacitors (MIPs) were fabricated from nanocarbon electrodes and a glyme-based electrolyte system via an in situ electrochemical oxidation process. A redox-free nanocarbon electrode was tuned into a pseudocapacitive nanocarbon anode (PNA) through a well-controlled oxidation process, showing an approximately 4 times higher specific capacitance value (~196 F g-1) compared with its initial EDL capacitance. The high-capacitance PNA can work in a wide voltage range of 4 V. Therefore, the PNA-based MIP showed a high specific energy density of 167 Wh kg-1, which is much higher than those of previously reported alkali-ion capacitors. Additionally, MIP full cell was achieved over 1,000 cycles.