Kaiyuan Shi

The increasing demand for high-performance energy devices has prompted the exploration of advanced electrolytic solutions for aqueous energy storage. Redox-enhanced Zn-ion capacitors (RZICs) overcome the limitations of conventional electrochemical capacitors by integrating redox-active molecules into the electrolyte, which enables higher energy density and expanded voltage windows. In this study, we developed organic dye-based colorimetric indicators for the fabrication of functional electrolytes in RZICs. The structural responsiveness of these dyes, driven by proton–electron transfer through electrochromic dynamics, allows real-time monitoring and optimization of the RZICs. The acid–base equilibrium of colorimetric indicators supports pH buffering, resulting in an extended lifespan of Zn||Zn cells up to 4,000 h. The conjugated aromatic structure of the indicators enhances their adsorption onto activated carbon, thereby minimizing the self-discharge in RZICs. Additionally, the phenol–quinone transformation increases the capacity of RZICs to 152.4 mAh g ⁻¹ within an optimized voltage window of 0.2–1.6 V, while promoting electrochemical kinetics and suppressing anode degradation. The results advance the design and customization of redox electrolytes with colorimetric properties for supercapacitive energy storage.

The incorporation of redox-active molecules into aqueous electrolytes addressed the challenges in the development of energy storage devices by enhancing energy density, expanding voltage windows, and improving cycling stability. Aqueous zinc-ion hybrid capacitors (ZICs), which combine the characteristics of metal-ion batteries and supercapacitors, have emerged to meet high energy-power demands. Herein, we investigate the irreversible and reversible dynamics of azobenzene compounds in the development of redox electrolytes for ZIC applications. The results reveal that Sunset Yellow (SY) additives promote reversible Zn²⁺ stripping/plating at the Zn anode through ion–ligand coordination, while the redox behavior of the –NN– group enhances the interfacial charge transfer. The passivation behavior of redox electrolytes, derived by SY molecules, was investigated using in situ electrochemical atomic force microscopy. Morphology evolution, coupled with nanomechanical tests, shed light on the transformation of SY-containing electrolytes. The redox electrolytes improve the lifespan of Zn//Zn cells from 50 to 1700 cycles at 2 mA cm⁻² and 1 mA h cm⁻² by suppressing parasitic reactions and mitigating by-product formation. The redox-enhanced ZIC delivers an increased capacity of 113.3 mA h g⁻¹ with improved cycling stability, compared to 75.2 mA h g⁻¹ of ZnSO₄ electrolytes without SY molecules at 0.6 mA g⁻¹. A range of azobenzene-based compounds with varying structures were investigated to demonstrate the synergistic modulating effects. The results demonstrate the molecular engineering of redox electrolytes and provide fundamental insights into electrochemical interphase transformation.

鉴于锂离子电池的大规模使用，锂产品在能源领域中扮演着至关重要的角色。然而，由于锂资源供应不足，寻找高效的提锂方法已成为当务之急，目前，固态锂资源在全球锂供应量中占主要部分，因受限于锂提取技术，资源量更大的液态锂资源的开发却非常有限，且液态锂资源生产成本更低，生产流程更简单，环境更友好，具有广阔的开发前景。电化学提锂方法是一种潜力巨大的提取方法，该方法起源于摇椅电池，锂锰氧化物由于其优异性能，是理想的电化学提锂电极材料。锰基材料电化学提锂方法具有高效、环保、可控、经济等优点，可以实现高效的锂提取和分离，同时减少环境污染和生产成本。未来随着锂需求的不断增加，锰基材料电化学提锂方法将会成为锂提取的重要技术。

Vanadium oxide-based electrode materials have attracted increasing attention owing to their extraordinary capacitance and prolonged lifespan, excellent conductivity and outstanding electrochemical reversibility. However, the development of vanadium oxide-based integrated electrodes with outstanding capacitive performance is an enduring challenge. This research reports a facile method for structuring 3D Archimedean micro-supercapacitors (AMSCs) composed of Mo doped V–VO_0.2 (Mo@V–VO_0.2) based integrated electrodes with designable geometric shape, using computer-aided wire electric discharge machining (WEDM). The performance of Mo@V–VO_0.2 based AMSCs manufactured by different processing voltages of 60 V, 80 V and 100 V were evaluated. It was found that 80 V is the optimal processing voltage for manufacturing Mo@V–VO_0.2 based AMSCs with the best electrochemical performance. This device demonstrates superior capacitive behavior even at an ultra-high scan rate of 50, 000 mV s⁻¹, and achieves a good capacitance retention rate of 94.4% after 2000 cycles. Additionally, the characteristics of electric field distribution were also simulated for optimizing the geometric structure of the microdevices. This WEDM fabrication technique, which is easy, secure, patternable, efficient, economical, eco-friendly, and does not require binders or conductive additives, enables the development of high-capacity 3D pseudocapacitive micro-supercapacitors and demonstrates the great potential for metal oxide synthesis and microdevice manufacturing.

A scalable, binder-free and one-step electric discharge rusting technique is proposed to fabricate high performance Fe–Fe _{1− x} O based coplanar microsupercapacitors.