Synthesis of carbon-coated Mn3O4 nanoparticles as a high performance cathode material for zinc-ion batteries by the addition of polyacrylonitrile

In this paper, carbon-coated Mn₃O₄ nanoparticles were synthesized by sintering the gel containing manganese acetate, PAN and DMF. Being heated to 500 °C in air at a heat rate of 13 °C/min, and then taken out immediately from the furnace, the gel converted to carbon-coated Mn₃O₄ nanoparticles with 20–30 nm sized Mn₃O₄ nanoparticles encapsulated in PAN-derived carbon. Unlike electrospinning and subsequent sintering the electrospun precursor in an inert atmosphere to synthesize metal oxide/carbon composite fibers, carbon-coated Mn₃O₄ nanoparticles with the low carbon content of 8.9 % were produced by sintering the gel precursor in air. As a cathode material for ZIBs, carbon-coated-Mn₃O₄ nanoparticles exhibit a high capacity of 557 mAh g⁻¹ at a current density of 0.1 A g⁻¹ after 300 cycles and good capacity retention performance during cycling. Its high capacity and good capacity retention performance are attributed to its low carbon content and porous PAN-derived carbon coating. Its low carbon content minimizes the negative impact of PAN-derived carbon on its capacity; its porous PAN-derived carbon coating prevents the cracking of Mn₃O₄ nanoparticles during charging-discharging and improves the electronic conductivity of Mn₃O₄ nanoparticles. The simple conducted technology synthesizes the carbon-coated Mn₃O₄ nanoparticles with a high capacity and good capacity retention performance, which makes it a promising route in the commercial production of cathode materials for ZIBs.