Mn3O4/carbon nanotube nanocomposites recycled from waste alkaline Zn–MnO2 batteries as high-performance energy materials

Abstract

Alkaline zinc manganese dioxide (Zn–MnO2) batteries are widely used in everyday life. Recycling of waste alkaline Zn–MnO2 batteries has always been a hot environmental concern. In this study, a simple and cost-effective process for synthesizing Mn3O4/carbon nanotube (CNT) nanocomposites from recycled alkaline Zn–MnO2 batteries is presented. Manganese oxide was recovered from spent Zn–MnO2 battery cathodes. The Mn3O4/CNT nanocomposites were produced by ball milling the recovered manganese oxide in a commercial multi-wall carbon nanotubes (MWCNTs) solution. Scanning electron microscopy (SEM) analysis demonstrates that the nanocomposite has a unique three-dimensional (3D) bird nest structure. Mn3O4 nanoparticles are homogeneously distributed on MWCNT framework. Mn3O4/CNT nanocomposites were evaluated as an anode material for lithium-ion batteries, exhibiting a highly reversible specific capacitance of ~580 mAh·g−1 after 100 cycles. Moreover, Mn3O4/CNT nanocomposite also shows a fairly positive onset potential of −0.15 V and quite high oxygen reducibility when considered as an electrocatalyst for oxygen reduction reaction.