Search

Li‐rich Mn‐based layered oxides are regarded as the most promising cathode materials for advanced lithium‐ion batteries with energy density as high as 400 Wh kg−1. However, decline of capacity and discharge potential derived from phase transformation during cycling is still an obstacle for practical utilization of Li‐rich cathode materials. Undoubtedly, an in‐depth understanding origin and evolution of the phase transformation from bottom to top is crucial to solve the problem finally. Herein, the recent representative progress on Li‐rich cathode materials from top to bottom is summarized: starting from relationship between dimensions and performance, to evolution of phase transformation, finally to participation of anions during charge–discharge cycling. It systematically shows what happens in the different microscopic levels and how these phenomena relate to cycling of Li‐rich cathode materials with the help of emerging state‐of‐the‐art characterization techniques. On the basis of this progress, it is proposed that rational structural design can fully play its role to build high‐performance energy storage materials and enhance structural stability. [ABSTRACT FROM AUTHOR]

The most critical failures in solid‐state batteries, including interfacial detachment, cracks, and dendrite growth are coupled with or fundamentally belong to a class of overarching phenomena that may be broadly defined as mechanical processes. However, current research on mechanical processes is far from sufficient, and is in its infancy compared with studies of improving electrolyte ionic transportation and electrochemical stabilities. Even the physical significance of many mechanical parameters has not been clarified in this field and the corresponding characterization methods have not yet been widely established. Herein, this review focuses on the intrinsic mechanical parameters associated with the design and operation of solid‐state batteries and their characterization. Beginning with an overview of mechanical processes, key concepts in the context of solid‐state batteries (SSB) are defined. Next, the various characterization methods that have been applied to SSBs are described in detail, and the key results are reviewed. Additional methods applied in orthogonal areas are also included to emphasize the possible translational impact on the solid‐state battery field. Finally, perspectives on the challenges and development trends in mechanical characterization are proposed for further development in solid‐state batteries. [ABSTRACT FROM AUTHOR]

The Compliant Golden‐Hooped Rod is a magical staff wielded by the Monkey King, Sun Wukong. The magical heavy Iron Rod was originally left inside Dragon Palace by Yu the Great, after taming the flood. In article number 1803477 Xue‐Ping Gao and co‐workers report the design of NiCo2O4 nanofibers, just like The Compliant Golden‐Hooped Rod in Dragon Palace. Inside a Li–S battery, the electrolyte with yellow soluble polysulfides (the yellow fish) is like the flood. NiCo2O4 nanofibers allow 'magical' catalytic conversion of soluble intermediate polysulfides by strong chemical interactions. Heavy NiCo2O4 nanofibers enhance the volumetric capacity of sulfurbased composites, like the stabilizing Iron Rod in the Sea. [ABSTRACT FROM AUTHOR]