A novel Mo@VN/V2O3-Co3O4 composite as a stable catalyst for potassium‑oxygen batteries with excellent performance

The potassium‑oxygen battery (KOB) as the only new system in metal-air batteries does not generate singlet oxygen ( 1 O 2 ). It is a novel high-energy-density storage device which has attracted widespread attention. However, the low efficiency of potassium ion and oxygen transfer in KOB, along with slow kinetics, results in poor cycling stability. For this reason, a new composite catalytic material with a multicomponent Mo@VN/V 2 O 3 -Co 3 O 4 in cathode of KOB has been designed and prepared. The homologous heterostructure formed between VN and V 2 O 3 exhibits a good lattice match, enhancing the carrier mobility and electrochemical activity of the electrode, thereby increasing the discharge capacity of the KOB. The multicomponent active interface formed between Co 3 O 4 and VN/V 2 O 3 stimulates more electrons to participate in redox reactions, and the synergistic catalytic effect promotes the reversible decomposition of KO 2 , improving the cycle life of the KOB. The doping of Mo enables Mo 6+ to enter the V 2 O 3 lattice, replacing some V δ+ , which creates crystal defects that facilitate the rapid diffusion of K + and O 2 in the electrode. Final, the Mo@VN/V 2 O 3 -Co 3 O 4 is used as a cathode catalyst of KOB, shown discharge specific capacity of 1899.61 mAh·g −1 with a cycle life >170 cycles.