Flexible Quasi-Solid-State Aqueous Zinc-Ion Batteries: Design Principles, Functionalization Strategies, and Applications

Aqueous zinc-ion batteries (AZIBs) may have applications in macroscale energy storage on account of their advantages of high-safety, cost-effectiveness, and ecofriendliness. As a promising application, flexible quasi-solid-state AZIBs (FQAZIBs) can withstand mechanical deformation, and can act as favorable power supply devices for wearable electronics. As FQAZIBs are one of the most exciting and rapidly ongoing topics among aqueous batteries, it is critical yet timely to summarize the latest development in this field, providing the much-needed guidance for the fabrication of FQAZIBs. In this review, the recent progress and rational design strategies for FQAZIBs from mechanisms, design principles, and applications are systematically presented. First, the energy storage and flexible mechanisms of FQAZIBs are illuminated in detail. Subsequently, the design philosophies of FQAZIBs are also systematically elucidated. Moreover, the latest progress and practical applications of FQAZIBs in wearable electronics are reviewed in detail according to various functions such as compressibility, stretchability, electrochromic ability, anti-freezing ability, self-healing ability, self-charging properties, photodetecting function, shape memory, biodegradability, and actuated function. Finally, some applications and promising prospects in the research area of FQAZIBs are demonstrated to supply guidelines on the exploitation of their practical applications.