Tuning the electroactive surface species of electrocatalysts remains a significant challenge for achieving highly efficient oxygen evolution reactions. Herein, we propose an innovative in situ leaching strategy, modulated by cationic oxidation, to achieve active self-reconstruction of these catalysts. Vanadium is introduced as a cation into Ni3S2 and oxidized under low oxidative potential, leading to subsequent leaching into the electrolyte and triggering self-reconstruction. The structural evolution from V-Ni3S2 to Ni­(OH)2 and subsequently to NiOOH is identified by operando Raman as a three-step transition. In contrast, V-free Ni3S2 is unable to bypass the thermodynamically predicted nickel oxysulfide products to transform into active NiOOH. As a result, the self-restructured V-Ni3S2 only needs an ultralow overpotential of 155 mV at 10 mA cm–2, outperforming V-free Ni3S2 and many other advanced catalysts. This work provides new guidelines for manipulating in situ leaching to modulate the self-reconstruction of catalysts.

Metal oxides are a promising candidate for lithium-ion battery (LIB) anodes due to their high theoretical capacity and long cycle life but also face inherent poor conductivity and volume variation, making them difficult to promote the application. The cation substitution strategy is an important means to facilitate improved rate and cycling performance. However, the effect of cation substitution on electrochemical activity is multivariate and complex, and a comprehensive and systematic analysis is essential for understanding the relationship between components and properties. Herein, the aliovalent heterogeneous Cr-substituted MnO was used as a model to systematically investigate the effects of Cr substitution on the crystal structure, electron distribution, defect construction, and electrochemical reaction processes. Theoretical calculations and experimental results reveal that Cr substitution can effectively modulate the electronic structure, build a built-in electric field, generate cationic defects, and catalyze the electrochemical reaction process, thereby improving the electrode kinetics and electrochemical activity of active materials. When the optimized Mn 0.94 Cr 0.06 O was used as the anode for LIBs, a reversible capacity of 1547.3 mAh g −1 was obtained after 450 cycles at a current density of 1 C (1 C = 756 mA g −1 for half-cells), and a reversible capacity of up to 1126.2 mAh g −1 could be maintained even after 700 cycles at a current density of 2 C. The assembled Mn 0.94 Cr 0.06 O//LiCoO 2 full cell further confirms the scalability of the heterogeneous atom substitution strategy.

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The poor cycle performance of Li-rich cathode Li2MnO3, a promising cathode of the next-generation Li-ion batteries, limits its commercial applications. Transition metal (TM) doping is widely applied to optimize the...

MnO, as a promising anode for lithium-ion batteries, is easy to form high-valence manganese oxides during the battery operation, causing a continuous capacity increase and hindering practical applications. Herein, an effective approach for regulating the electrochemical capacity trend is presented with the guide of the thermodynamic calculations. According to the calculated Ellingham diagrams, the potential metals (Me = Fe, Sn, Co, Ni, and Cu) were selected to synthesize the Me–MnO composite anode materials. The cycling test results indicate that the selected metals show the abilities to inhibit the further oxidation of Mn2+ and regulate the capacity in the order of Fe < Sn < Co < Ni < Cu. The mechanism of the electrochemical reaction sequence is clarified based on the thermodynamic properties. This approach provides a rational design of electrode materials for improved performance via a hybrid electrochemistry-thermodynamics analysis.