Manganese oxide synthesized from spent Zn-C battery for supercapacitor electrode application (original) (raw)

Manganese oxide (Mn 3 o 4) nanomaterials have promising potential to be used as supercapacitor electrode materials due to its high energy storage performance and environmental compatibility. Besides, every year huge volume of waste batteries including Zn-C battery ends up in landfill, which aggravates the burden of waste disposal in landfill and creates environmental and health threat. Thus, transformation of waste battery back into energy application, is of great significance for sustainable strategies. Compared with complex chemical routes which mostly apply toxic acids to recover materials from Zn-C battery, this study establishes the recovery of Mn 3 o 4 particles via thermal route within 900 °C under controlled atmosphere. Synthesized Mn 3 o 4 were confirmed by XRD, EDS, FTIR, XPS and Raman analysis and FESEM micrographs confirmed the coexistence of spherical and cubic Mn 3 o 4 particles. Mn 3 o 4 electrode derived from waste Zn-C battery demonstrate compatible electrochemical performance with standard materials and conventional synthesis techniques. Mn 3 o 4 electrode exhibited highest capacitance value of 125 Fg −1 at 5 mVs −1 scan rate. the stability of the electrode showed good retention in discharge and charge capacity by about 80% after 2100 cycles. This study demonstrates that waste Zn-C battery can be further utilized for energy storage application, providing sustainable and economic benefits. Supercapacitor become more attractive and efficient energy storage and conversion devices than batteries due to high specific power, long life cycle and fast charge-discharge rate 1. Hence, supercapacitors are undergoing rapid development with widespread application in automobiles, electronics and in industries 1. Supercapacitors mainly consist of electrodes, current collectors, electrolyte and a spacer but electrodes are the key element of supercapacitor's performance 1-3. In general supercapacitor store energy via either electrical double layer capacitance (EDLC) principle or the pseudo-capacitance mechanism. Energy density in EDLC is managed by the electrostatic capability of the absorbing electrolytes (anions, cations), by active materials embedded within electrodes and therefore carbon materials such as, activated carbon, carbon nanotubes etc. with high surface area are used. Besides, in pseudo-capacitance mechanism, energy density is governed by reversible redox interactions of the active materials as electrode and generally transition metal oxides and conducting polymers are used as active materials 1,4,5. Nanostructured metal oxides as electrode material, have attracted attention due to design flexibility, low resistance and high specific capacitance 6. Manganese oxide (MnO x) has a wide range of applications including catalysis, electrochemical materials, high-density magnetic storage media etc. Recently, MnOx materials including Mn 3 O 4 were substantially reported as supercapacitor electrode materials due to its environmental compatibility, low cost and good electrochemical performance compared to other oxides like ruthenium oxide 7. Mn 3 O 4 materials for different application covers a wide range of synthesis routes including reduction, thermal decomposition, coprecipitation, hydrothermal, sol-gel 8-10 etc. using reagent grade materials. Besides, Mn 3 O 4 /Mn 3 O 4-composite materials for supercapacitor application includes electrostatic spray deposition, hydrothermal synthesis etc. techniques 11-13. However, the synthesis routes and preparation techniques are complex and may use toxic acid. The use of waste carbonaceous materials like bio-waste, polymers etc. have been reported for energy storage applications, but metal oxides from waste were ignored. To best our knowledge, no study has reported Mn 3 O 4 from