Comparative study on the electrochemical performance of β-manganese dioxide-3D graphene mixtures with (without) carbon nanotubes

Manganese dioxide is widely used as a cathode material in aqueous zinc-ion batteries, and the cathode material is a key factor limiting the performance of these batteries. In this study, β-manganese dioxide was used as the base material to synthesize two hybrid materials, i.e. manganese dioxide-3D graphene carbon nanotube hybrids (MnO₂@3D-GPE/CNT) and manganese dioxide-3D-graphene hybrids (MnO₂@3D-GPE), via intermittent high-energy vibration ball milling. Electrochemical tests revealed that the CNT-containing hybrid materials exhibited a higher specific capacity of 480 mAh g⁻¹ and superior cycling stability, maintaining over 80% of its initial capacity after 1000 cycles at 500 mA g⁻¹ with a Coulombic efficiency close to 100%. MnO₂@3D-GPE/CNT had a smaller particle size distribution and a larger specific surface area than MnO₂@3D-GPE, explaining its enhanced electrochemical performance. Additionally, MnO₂@3D-GPE/CNT exhibited lower electrode impedance, further supporting its efficacy as a cathode material.