Batteries
Advanced energy storage systems hold critical signifcance in satisfying the ever-increasing global demand for energy. And as a viable and efective alternative to lithium-ion batteries that dominate the current energy market, Zn-based batteries[i.e. Zn-ion batteries (ZIBs) and Zn-air batteries (ZABs)] have attracted extensive research eforts. Zn metal possesses many advantages because of its high theoretical capacity, its inexpensiveness and its good safety characteristic, and in recent years, tremendous eforts have been carried out to accelerate the development of ZIBs and ZABs with various electrode materials and electrocatalysts being proposed and investigated. In addition, with advances in characterization techniques, the underlying reaction mechanisms of these materials are also being elucidated. Therefore, this review will provide a comprehensive summary of the latest progress in various electrode materials adopted in the current ZIBs and ZABs along with corresponding mechanisms. Specifcally, Mn- and V-containing cathode materials for ZIBs and associated reaction mechanisms will be thoroughly discussed, and emerging cathodes such as Prussian blue analogues, NASICON-type nanostructures and organic compounds will be presented. In terms of ZABs, this review will discuss three major types of electrocatalysts, including noble metals, heteroatom-doped carbons and transition metal oxides/sulphides/phosphides/nitrides. In addition, as a critical factor in the performance of Zn-based batteries, challenges encountered by the current Zn anodes and strategies developed to tackle these issues will be discussed as well. Finally, a short summary including the current progress and future perspectives of ZIBs and ZABs will be provided.
Full-text:https://link.springer.com/article/10.1007/s41918-019-00035-5/fulltext.html
Flow batteries have received increasing attention because of their ability to accelerate the utilization of renewable energy by resolving issues of discontinuity, instability and uncontrollability. Currently, widely studied fow batteries include traditional vanadium and zinc-based fow batteries as well as novel fow battery systems. And although vanadium and zinc-based fow batteries are close to commercialization, relatively low power and energy densities restrict the further commercial and industrial application. To improve power and energy densities, researchers have started to investigate novel fow battery systems, including aqueous and non-aqueous systems. Here, novel non-aqueous fow batteries possess low conductivity and low safety, limiting further application. Therefore, the most promising systems remain vanadium and zinc-based fow batteries as well as novel aqueous fow batteries. Overall, the research of fow batteries should focus on improvements in power and energy density along with cost reductions. In addition, because the design and development of fow battery stacks are vital for industrialization, the structural design and optimization of key materials and stacks of fow batteries are also important. Based on all of this, this review will present in detail the current progress and developmental perspectives of fow batteries with a focus on vanadium fow batteries, zinc-based fow batteries and novel fow battery systems to provide an efective and extensive understanding of the current research and future development of fow batteries.
Full-text:https://link.springer.com/article/10.1007/s41918-019-00047-1/fulltext.html