Doping-Induced Static Activation of MnO₂ Cathodes for Aqueous Zn-Ion Batteries

Abstract

Electrochemical activation has been confirmed to be a powerful strategy to improve the Zn2+ storage activity of MnO2-based cathodes. A pivotal challenge of electrochemical activation is the poor cycling stability of activated cathodes upon Zn2+ (de)­intercalation due to the dissolution of active materials in the electrolyte, the structural degeneration of pristine cathode materials, and the complicated dynamic electrochemical process. In this study, we report a novel doping-induced static activation method to induce the formation of active Zn3V2O7(OH)2­·2H2O (ZVO) on the surface of a highly V-doped MnO2 (VMO) cathode by simply placing the cathode in an aqueous ZnSO4 electrolyte for 10 days. Our method not only significantly improves the Zn2+ storage activity of the pristine VMO cathode but also successfully tackles these problems of electrochemical activation. The activated cathode (VMO/ZVO) delivers a significantly increased initial capacity of 262 mA h g–1 and a high capacity retention of 99% after 100 cycles based on a H+/Zn2+ synergetic pseudocapacitive mechanism. The proposed static activation strategy holds great potential in the fabrication of high-activity cathodes for aqueous Zn-ion batteries.

Selenium-Doped Amorphous Black Phosphorus@TiO2/C Heterostructures for High-Performance Li/Na/K Ion Batteries

“…Conversely, as the scan rate exceeds 2 mV s –1 , a significant capacity decay is observed in region 2, which reflects a rate-dependent diffusion process. The capacitive and diffusion capacities can be further separated by the k 1 – k 2 analysis, as shown in formula , the capacitive capacity is ∼86.4% of the total capacity at 2 mV s –1 (the inset of Figure c), while the remaining capacity is close to the redox peaks, which is attributed to the Li + diffusion in the active materials. At other scan rates, these specific capacities also mainly come from the capacitive contribution (Figure d).…”

Construction of Bio‐inspired Film with Engineered Hydrophobicity to Boost Interfacial Reaction Kinetics of Aqueous Zinc–Ion Batteries

“…This phenomenon is ascribed to the co-insertion of proton and Zn 2+ , thereby causing the decrease of manganese valence. [23,65] When charging to 1.8 V, the Mn 2p peaks almost recover their initial state, further suggesting the desired reversibility. Based on this analysis, the Zn 2+ storage mechanism in the PMC-8 cathode is possible via H + and Zn 2+ co-insertion/extraction in the tunnel-type structure, and the corresponding reactions are summarized as follows: [39,44] Cathode:…”

Unraveling high-performance oxygen-deficient amorphous manganese oxide as the cathode for advanced zinc ion batteries

“…13 Subsequently, material doping and composite synthesis were also explored. Interestingly, doping this material with elements such as nitrogen or other metals 14,15 helped increase the ion diffusion properties while composite synthesis such as carbon-based composites enhanced the material's conductivity and surface energy.…”