Batteries
Advanced electrodes with excellent rate performance and cycling stability are in demand for the fast development of sodium storage. Two-dimensional (2D) materials have emerged as one of the most investigated subcategories of sodium storage related anodes due to their superior electron transfer capability, mechanical flexibility, and large specific surface areas. Recently, 2D metal carbides and nitrides (MXenes), one type of the new 2D materials, are known to have competitive advantages in terms of high electroconductivity, terminal functional groups, large specific surface areas, tunable interlayer spacing, and remarkable safety. These advances endow MXenes and MXene-based materials with superior electrochemical performance when they are used as electrodes for sodium-ion storage. MXenes, however, share similar defects with other 2D materials, such as serious restacking and aggregation, which need to be improved in consideration of their further applications. In this review, we present the big family of MXenes and their synthetic methods. Furthermore, recent research reports related to progress on MXene-based materials for sodium storage are compiled, including materials design and reaction mechanisms in sodium-ion batteries and sodium metal batteries. Significantly, we discuss the challenges for existing MXene-based structures with respect to their future use as electrodes, such as low capacitance, aggregation, untenable termination groups, and unclear mechanisms, thereby providing guidance for future research on MXene-based materials for sodium-ion storage.
Full-text：https://link.springer.com/article/10.1007/s41918-020-00079-y
All-solid-state lithium batteries (ASSLBs) have attracted increasing attention due to their high safety and energy density. Among all corresponding solid electrolytes, sulfide electrolytes are considered to be the most promising ion conductors due to high ionic conductivities. Despite this, many challenges remain in the application of ASSLBs, including the stability of sulfide electrolytes, complex interfacial issues between sulfide electrolytes and oxide electrodes as well as unstable anodic interfaces. Although oxide cathodes remain the most viable electrode materials due to high stability and industrialization degrees, the matching of sulfide electrolytes with oxide cathodes is challenging for commercial use in ASSLBs. Based on this, this review will present an overview of emerging ASSLBs based on sulfide electrolytes and oxide cathodes and highlight critical properties such as compatible electrolyte/electrode interfaces. And by considering the current challenges and opportunities of sulfide electrolyte-based ASSLBs, possible research directions and perspectives are discussed.
Full-text：https://link.springer.com/article/10.1007/s41918-020-00081-4
Aqueous rechargeable batteries (ARBs) have become a lively research theme due to their advantages of low cost, safety, environmental friendliness, and easy manufacturing. However, since its inception, the aqueous solution energy storage system has always faced some problems, which hinders its development, such as the narrow electrochemical stability window of water, poor percolation of electrode materials, and low energy density. In recent years, to overcome the shortcomings of the aqueous solution-based energy storage system, some very pioneering work has been done, which also provides a great inspiration for further research and development of future high-performance aqueous energy storage systems. In this paper, the latest advances in various ARBs with high voltage and high energy density are reviewed. These include aqueous rechargeable lithium, sodium, potassium, ammonium, zinc, magnesium, calcium, and aluminum batteries. Further challenges are pointed out.
Full-text：https://link.springer.com/article/10.1007/s41918-020-00075-2
To address increasing energy supply challenges and allow for the effective utilization of renewable energy sources, transformational and reliable battery chemistry are critically needed to obtain higher energy densities. Here, significant progress has been made in the past few decades in energetic battery systems based on the concept of multi-electron reactions to overcome existing barriers in conventional battery research and application. As a result, a systematic understanding of multi-electron chemistry is essential for the design of novel multi-electron reaction materials and the enhancement of corresponding battery performances. Based on this, this review will briefly present the advancements of multi-electron reaction materials from their evolutionary discovery from lightweight elements to the more recent multi-ion effect. In addition, this review will discuss representative multi-electron reaction chemistry and materials, including ferrates, metal borides, metal oxides, metal fluorides, lithium transition metal oxides, silicon, sulfur and oxygen. Furthermore, insertion-type, alloy-type and conversion-type multi-electron chemistry involving monovalent Li+ and Na+ cations, polyvalent Mg2+ and Al3+ cations beyond those of alkali metals as well as activated S2- and O2- anions are introduced in the enrichment and development of multi-electron reactions for electrochemical energy storage applications. Finally, this review will present the ongoing challenges and underpinning mechanisms limiting the performance of multi-electron reaction materials and corresponding battery systems.
Full-text：https://link.springer.com/article/10.1007/s41918-020-00073-4
