Chumkaeo P.Promcharoen P.Charoenchaidet S.Charoenchaidet S.Somsook E.Mahidol University2026-03-052026-03-052026-05-15Materials Letters Vol.411 (2026)0167577Xhttps://repository.li.mahidol.ac.th/handle/123456789/115561A Fe<inf>2</inf>O<inf>3</inf>-MnO<inf>X</inf>-graphene carbon composite was synthesized via a facile calcination route using ferrocene and potassium permanganate as combined metal and carbon precursors, followed by KOH activation. During thermal treatment, the cyclopentadienyl ligands of ferrocene were converted into a graphene-like carbon matrix, while iron and manganese species were simultaneously transformed into Fe<inf>2</inf>O<inf>3</inf> and MnO<inf>X</inf>, respectively. Chemical activation introduced hierarchical porosity and enhanced electrochemical accessibility. The activated composite delivered a specific capacitance of 173.9 F g⁻¹ at 0.5 A g⁻¹ and retained 78.5% of its initial capacitance after 2000 charge–discharge cycles at 5 A g⁻¹.Materials SciencePhysics and AstronomyEngineeringArticleSCOPUS10.1016/j.matlet.2026.1403112-s2.0-10503131050818734979