Systematic investigation of the electrochemical performance of MnO₂-based supercapacitors enabled by expanded graphite integration

TAŞDEMİR R., ÇIPLAK Z., YILDIZ N., YAPICI K.

Journal of Applied Electrochemistry, cilt.56, sa.4, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 56 Sayı: 4
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1007/s10800-026-02457-8
  • Dergi Adı: Journal of Applied Electrochemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, INSPEC
  • Anahtar Kelimeler: Electrochemical performance, Energy storage devices, Expanded graphite/MnO₂ composites, Supercapacitor electrodes
  • Sivas Cumhuriyet Üniversitesi Adresli: Evet

Özet

This study systematically investigates the performance of MnO2​/EG composite electrodes, formed with expanded graphite (EG), to overcome the electrochemical limitations arising from the inherently low electrical conductivity of MnO2​. The composites, prepared with varying mass ratios from 0% to 40% EG content, are evaluated through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) analyses. The results reveal that the addition of EG effectively mitigates both the kinetic and structural limitations of MnO2​, leading to a synergistic enhancement in performance. Specifically, the M80E20 electrode, containing 20% EG, is identified as the optimal composition. It exhibits the highest specific capacitance of 328.7 F g⁻¹ at 2 mV s⁻¹, the best rate capability with 47% capacitance retention at 100 mV s⁻¹, and superior cycling stability, showing 77% capacitance retention after 2000 cycles. Ragone analysis demonstrates that the symmetric device fabricated with this composite delivers a high energy and power density profile, suggesting that supercapacitor performance can be significantly enhanced. The findings indicate that the EG additive functions not merely as a conductive support but as a multifunctional structural backbone that accelerates ion and electron transport and preserves structural integrity.