Efficient asymmetric diffusion channel in MnCo 2 O 4 spinel for ammonium-ion batteries.

Transition metal oxides ion diffusion channels have been developed for ammonium-ion batteries (AIBs). However, the influence of microstructural features of diffusion channels on the storage and diffusion behavior of NH ₄ ⁺ is not fully unveiled. In this study, by using MnCo ₂ O ₄ spinel as a model electrode, the asymmetric ion diffusion channels of MnCo ₂ O ₄ have been regulated through bond length optimization strategy and investigate the effect of channel size on the diffusion process of NH ₄ ⁺ . In addition, the reducing channel size significantly decreases NH ₄ ⁺ adsorption energy, thereby accelerating hydrogen bond formation/fracture kinetics and NH ₄ ⁺ reversible diffusion within 3D asymmetric channels. The optimized MnCo ₂ O ₄ with oxygen vacancies/carbon nanotubes composite exhibits impressive specific capacity (219.2 mAh g ^-1 at 0.1 A g ^-1 ) and long-cycle stability. The full cell with 3,4,9,10-perylenetetracarboxylic diimide anode demonstrates a remarkable energy density of 52.3 Wh kg ^-1 and maintains 91.9% capacity after 500 cycles. This finding provides a unique approach for the development of cathode materials in AIBs.
Competing Interests: Competing interests statement:The authors declare no competing interest.