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Repozytorium publikacji
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Diamond-Based Supercapacitors with Ultrahigh Cyclic Stability Through Dual-Phase MnO2-Graphitic Transformation Induced by High-Dose Mn-Ion Implantation

While occasionally being able to charge and dischargemore quickly than batteries, carbon-based electrochemical supercapacitors(SCs) are nevertheless limited by their simplicity of processing, adjustableporosity, and lack of electrocatalytic active sites for a range of redox reactions.Even SCs based on the most stable form of carbon (sp3carbon/diamond)have a poor energy density and inadequate capacitance retention during longcharge/discharge cycles, limiting their practical applications. To constructa SC with improved cycling stability/energy density Mn-ion implanted(high-dose; 1015–1017ions cm−2) boron doped diamond (Mn-BDD) films havebeen prepared. Mn ion implantation and post-annealing process results in anin situ graphitization (sp2phase) and growth of MnO2phase with roundishgranular grains on the BDD film, which is favorable for ion transport. The dualadvantage of bothsp2(graphitic phase) andsp3(diamond phase) carbonswith an additional pseudocapacitor (MnO2) component provides a unique andcritical function in achieving high-energy SC performance. The capacitance ofMn-BDD electrode in a redox active aqueous electrolyte (0.05 M Fe(CN)63-/4−+1MNa2SO4)isashighas51mFcm−2at 10 mV s−1with exceptionalcyclic stability (≈100% capacitance even after 10 000 charge/dischargecycles) placing it among the best-performing SCs. Furthermore, the ultrahighcapacitance retention (≈80% retention after 88 000 charge/discharge cycles)in a gel electrolyte containing a two-electrode configuration shows a promisingprospect for high-rate electrochemical capacitive energy storage applications.

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