Electrochemical performance studies of MnO₂ nanoflowers recovered from spent battery

Highlights: • MnO₂ is recovered from spent zinc–carbon batteries as nanoflowers structure. • Recovered MnO₂ nanoflowers show high specific capacitance. • Recovered MnO₂ nanoflowers show stable electrochemical cycling up to 900 cycles. • Recovered MnO₂ nanoflowers show low resistance in EIS data. - Abstract: The electrochemical performance of MnO₂ nanoflowers recovered from spent household zinc–carbon battery is studied by cyclic voltammetry, galvanostatic charge/discharge cycling and electrochemical impedance spectroscopy. MnO₂ nanoflowers are recovered from spent zinc–carbon battery by combination of solution leaching and electrowinning techniques. In an effort to utilize recovered MnO₂ nanoflowers as energy storage supercapacitor, it is crucial to understand their structure and electrochemical performance. X-ray diffraction analysis confirms the recovery of MnO₂ in birnessite phase, while electron microscopy analysis shows the MnO₂ is recovered as 3D nanostructure with nanoflower morphology. The recovered MnO₂ nanoflowers exhibit high specific capacitance (294 F g⁻¹ at 10 mV s⁻¹; 208.5 F g⁻¹ at 0.1 A g⁻¹) in 1 M Na₂SO₄ electrolyte, with stable electrochemical cycling. Electrochemical data analysis reveal the great potential of MnO₂ nanoflowers recovered from spent zinc–carbon battery in the development of high performance energy storage supercapacitor system