Alkaline zinc–air batteries are promising energy storage technologies with the advantages of low cost, ecological friendliness, and high energy density. However, the rechargeable zinc–air battery has not been used on a commercial scale because the zinc electrode suffers from critical problems such as passivation, dendrite growth, and hydrogen evolution reaction, which limit the practical applications of zinc–air batteries. Herein, the Perspective summaries the solutions to minimize the negative effects of zinc electrodes on discharge performance, cycling life, and shelf life. The future direction of academic research based on current studies of the existing challenges is proposed.

With the low redox potential of −3.04 V (vs SHE) and ultrahigh theoretical capacity of 3862 mAh g −1 , lithium metal has been considered as promising anode material. However, lithium metal battery has ever suffered a trough in the past few decades due to its safety issues. Over the years, the limited energy density of the lithium-ion battery cannot meet the growing demands of the advanced energy storage devices. Therefore, lithium metal anodes receive renewed attention, which have the potential to achieve high-energy batteries. In this review, the history of the lithium anode is reviewed first. Then the failure mechanism of the lithium anode is analyzed, including dendrite, dead lithium, corrosion, and volume expansion of the lithium anode. Further, the strategies to alleviate the lithium anode issues in recent years are discussed emphatically. Eventually, remaining challenges of these strategies and possible research directions of lithium-anode modification are presented to inspire innovation of lithium anode.

The development of efficient and low-cost flexible metal electrodes is significant for flexible rechargeable zinc−air batteries (ZABs). Herein, we reported a new type of flexible metal (zinc and nickel) electrode fabricated via a two-step deposition method on polyurethane sponges (PUS) for flexible ZABs. Compared to conventional electrodes, the metal-coated PUS electrodes exhibited great flexibility, softness, and natural mechanical resilience. In addition, a flexible sandwich-structured ZAB was assembled with the metal-coated PUS electrodes and in situ cross-linked polyacrylic acid (PAA)−KOH hydrogel electrolyte. The flexible ZAB presented stable discharge/charge performance even under complex rolling and twisting deformations. Moreover, inspired by the kirigami-strategy for device-level stretchability, a 100% stretchable fence-shaped ZAB and a 160% stretchable serpentine-shaped ZAB were cut from the abovementioned flexible ZABs. The kirigami-inspired configuration enabled the battery performance to be stable during stretching, benefiting from the softness of the PUS@metal electrode. These flexible and stretchable ZABs would broaden the promising applications for portable and wearable energy storage devices.

Energy and environmental issues received widespread attentions due to the fast growth of world population and rapid development of social economy. As a transition metal dichalcogenide, tungsten disulfide (WS 2) nanomaterials make important research progress in the field of energy conversion and storage. In view of the versatile and rich microstructure of these materials, the modification and controllable synthesis of WS 2 nanomaterials also inspire a research interest. This review mainly focuses on WS 2-based nanomaterials in the application of energy conversion and storage as well as discusses some basic characteristics and modification strategies of them. Finally, the research progress of WS 2-based nanomaterials is reviewed and some prospects for future research directions are proposed. This review is expected to be beneficial to the future study of WS 2 nanomaterials used in the field of energy conversion and storage.

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In recent years, with the increasing application of lithium-ion batteries in energy storage devices, fire accidents caused by lithium-ion batteries have become more frequent and have arisen wide concern. Due to the safety of aqueous electrolyte, aqueous Zn-based batteries have attracted vast attention, among which Zn–Ni batteries stand out by virtue of their excellent rate performance and environmental friendliness. However, poor cycling life limits the application of Zn–Ni batteries. To figure out the main cause, a failure analysis of a practical Zn–Ni battery has been carried out. During the cycling of the Zn–Ni battery, the evolution of gas, the shape changing, and the aggregation of additive and binder of Zn anode can be observed. Combined with the finite element analysis, we finally reveal that the key factor of battery failure is the shape changing of the Zn anode caused by uneven current distribution and the dissolution of Zn. The shape changing of the Zn anode reduces the effective surface area of anode and increases the possibility of dead Zn, which makes the battery unable to discharge even in the presence of a large amount of Zn. These findings are helpful to deepen the understanding of the working and failure mechanisms of the Zn anode and provide effective guidance for subsequent research.

Because of their high theoretical value of volumetric energy density, excellent rate performance, and high level of safety, zinc–nickel batteries (ZNBs) show potential applications for uninterrupted power supply (UPS) systems. However, despite all the advantages of ZNBs, the commercial application of ZNBs has been prevented by their short lifetime caused by the shape change, the corrosion, and the dendrite formation of the Zn anode. In this work, we proposed a flexible and durable potassium polyacrylate (PAAK)–KOH gel polymer electrolyte (GPE) prepared in a very simple way to solve the above problems of the Zn anode. The obtained highly porous gel electrolyte showed higher water retention, satisfying ionic conductivity (0.918 S cm–1), and a broad electrochemical stable voltage window. By providing a stable and homogeneous electrode/electrolyte interface for the Zn anode, the gel electrolyte can inhibit the uneven deposition and dendrite formation. As a result, the gel electrolyte greatly prolonged the cycling life to 776 h. In addition, because of the considerably batter corrosion resistance of the Zn anode in the PAAK–KOH GPE, the ZNB with gel electrolyte also exhibited a superior shelf life of more than 431 h and a superior cycling performance under float charge for more than 400 h at 60 °C. This work demonstrates that the gel electrolyte with a simple preparation method is suitable for large-scale practical production and can be successfully used in Zn–Ni batteries as an electrolyte exhibiting excellent performance.

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