Electrodes with nanosheet architectures can offer the possibility to achieve enhanced energy storage performance. Herein, we have designed and synthesized novel nanosheet structures of CoAl layered double hydroxide (LDH)-polyaniline (PANI) nanocomposite thin films by a hydrothermal-electrodeposition method. The molecular structure, crystal structure, morphology and chemical composition of the composites were characterized by FT-IR, XRD (SXRD), FESEM, and XPS, whereas their electrochemical properties were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge tests. Compared with the unmodified CoAl LDH, the CoAl LDH-PANI exhibits significantly improved the specific capacitance and cyclic stability. The composite exhibits a high specific capacitance of 528 F/g at a current density of 10 A/g and excellent cyclic stability with an increase of the specific capacitance of 42.7% after 6000 cycle tests. We revealed the degradation behavior of PANI in 1 M KOH/KCl electrolyte, and the active degradation products also further increased the total specific capacitance of the composite. The enhanced electrochemical performance of the nanocomposite can be attributed to its well-designed nanostructure and the synergistic effects of each component. By analyzing the band structure and density of states of CoAl LDH and PANI, we proposed the possible mechanism of synergistic effect in a new perspective.

The global imperative for sustainable energy has catalyzed the pursuit of next-generation energy storage technologies that are intrinsically safe, economically viable, and scalable. Aqueous zinc-ion batteries (AZIBs) present a promising solution to meet these demands. However, the metallic Zn anode, the heart of this technology, suffers from fundamental electrochemical instabilities—manifesting as dendrite growth and rampant parasitic reactions (e.g., corrosion and passivation)—that critically curtail battery lifespan and impede practical application. This review offers a comprehensive overview of the latest strategies designed to achieve a highly reversible and stable Zn anode. We meticulously categorize and analyze these innovations through the three integral components of the AZIBs: (i) intrinsic anode engineering, (ii) interfacial electrolyte chemistry regulation, and (iii) separator-induced transport modulation. By delving into the core scientific mechanisms and critically evaluating each approach, this work synthesizes a holistic understanding of the structure-property-performance relationships. We conclude by identifying the persistent challenges and, more importantly, proposing visionary perspectives on future research directions. This review aims to serve as a scientific guide for the rational design of highly reversible Zn anodes, paving the way for the next generation of high-performance, commercially viable aqueous batteries.

Zinc–manganese dioxide (Zn–MnO₂) batteries, pivotal in primary energy storage, face challenges in rechargeability due to cathode dissolution and anode corrosion. This review summarizes cathode-free designs using pH-optimized electrolytes and modified electrodes/current collectors. For electrolytes, while acidic systems with additives (PVP, HAc) enhance ion transport, dual-electrolyte configurations (ion-selective membranes/hydrogels) reduce Zn corrosion. Near-neutral strategies utilize nanomicelles/complexing agents to regulate MnO₂ deposition. Moreover, mediators (I⁻, Br⁻, Cr³⁺) reactivate MnO₂ but require shuttle-effect control. For the electrodes/current collectors, electrode innovations including SEI/CEI layers and surfactant-driven phase tuning are introduced. Electrode-free designs and integrated “supercapattery” systems combining supercapacitors with Zn–MnO₂/I₂ chemistries are also discussed. This review highlights electrolyte–electrode synergy and hybrid device potential, paving the way for sustainable, high-performance Zn–MnO₂ systems.

Flexible zinc-ion batteries (ZIBs) are emerging as a highly promising energy storage technology for wearable electronics due to their intrinsic safety, low cost, abundant materials, and environmental friendliness. However, persistent challenges in aqueous ZIBs—such as dendrite growth, parasitic reactions on the zinc anode, and the dissolution of cathode materials—continue to hinder their practical implementation. Hydrogel electrolytes, functioning as quasi-solid-state ionic conductors, not only impart outstanding mechanical flexibility and processability but also effectively stabilize the electrode–electrolyte interfaces, positioning them as ideal candidates for next-generation wearable electronics. This review offers a comprehensive summary of recent advancements in hydrogel electrolytes for flexible ZIBs. Initially, the fundamental working principles and material challenges of ZIBs are discussed. The physicochemical properties, synthesis approaches, and structural design strategies for hydrogel electrolytes are then thoroughly examined. Next, we highlight cutting-edge strategies aimed at stabilizing both the zinc anode and various cathode materials by rationally tailoring hydrogel chemistry. Particular attention is given to multifunctional hydrogels engineered to operate under diverse conditions, including low/high-temperature tolerance, self-healing, and biocompatibility. Furthermore, the integration of hydrogel electrolytes into ZIBs and their potential applications in wearable sensors, electronic skin, and flexible touch interfaces are reviewed. Lastly, we provide a critical outlook on current challenges and future research directions, emphasizing the urgent need for enhanced multifunctionality, scalability for pouch cells, and standardized testing protocols. This comprehensive review is intended not only to elucidate the state of the art, but also to inspire innovative strategies, thereby facilitating the transition of hydrogel-based flexible ZIBs from laboratory research to real-world applications

For electric energy storage device, electrodes with nanosheet architectures can offer the possibility to achieve enhanced energy storage performance. Layered double hydroxide (LDH) is one of the candidate of electrode materials for electrochemical capacitor. Herein, we have successfully synthesized CoAl, NiAl and NiFe LDH nano-films grown on Ni substrate by hydrothermal methods. For CoFe, LDH nano-film cannot be obtained using same experiment conditions. SEM micrographs show that the thickness of LDH layered nanosheet are ~100, ~ 40 and ~85 nm for CoAl, NiAl and NiFe samples. The LDHs nanosheet film were grown perpendicularly on the substrate as electrode materials. The electrochemical performance of LDHs were tested by cyclic voltammetry. The measured cyclic voltammograms indicated that CoAl LDH has the best reversibility and the highest capacitance (554 F/g) among the three types of LDHs. A good cycling stability was also observed for the CoAl LDH nanosheet with the specific capacitance remained at 425 F/g and retained 77.3% of the high value after 6000 cycles at current density 10A/g.