Mascarenhas, F.J.Rodney, J.D.Kim, B.C.Badekai Ramachandra, B.R.2026-02-042024Journal of Alloys and Compounds, 2024, 986, , pp. -9258388https://doi.org/10.1016/j.jallcom.2024.173957https://idr.nitk.ac.in/handle/123456789/21123The demand for electrode materials in supercapacitors necessitates designs with exceptional performance, superior structure, and environmental sustainability, all while remaining affordable and abundantly available. This study introduces an economical hydrothermal synthesis method for producing M<inf>x</inf>Mn<inf>1-x</inf>Se (M=Co / Ni / Zn) nanomaterials at varying concentrations (x = 0.0, 0.01, 0.02, and 0.03). Diverse characterization methods confirm the successful formation of nanomaterials. Among the materials studied, Co<inf>0.01</inf>Mn<inf>0.99</inf>Se nanoclusters exhibit superior performance as electrode materials for supercapacitors, delivering a specific capacitance of 421 F/g at 5 mV/s and 377 F/g at 1 A/g in a 5 M KOH solution. A two-electrode symmetric configuration was established utilizing Co<inf>0.01</inf>Mn<inf>0.99</inf>Se as the active material in a 5 M KOH electrolyte, yielding a notable specific capacitance of 73 F/g at 0.5 A/g. The maximum energy density and power density achieved are 20.44 Wh/kg and 2838 W/kg respectively. This configuration demonstrates the exceptional electrochemical performance and energy storage capabilities of Co<inf>0.01</inf>Mn<inf>0.99</inf>Se in a two-electrode system. Impressively, the symmetric cell maintains a significant 70% capacitance retention even after 5000 charge-discharge cycles. Considering these findings, the developed Co<inf>0.01</inf>Mn<inf>0.99</inf>Se emerges as a pivotal advancement, providing a robust framework for the development of cutting-edge energy conversion and storage technologies. © 2024 Elsevier B.V.CapacitanceCobalt compoundsCobalt depositsElectric dischargesElectrochemical electrodesElectrolytesManganese compoundsNanostructured materialsNickelNickel compoundsPotassium hydroxideSelenium compoundsSupercapacitorZinc compoundsAdvanced energy conversionCo-dopingElectrode materialMnse nanomaterialNi-dopingPerformanceSpecific capacitanceSupercapacitor electrodesSymmetricsZn dopingHydrothermal synthesis