The microstructural degradation, stabilization, and characterization of layered Ni-rich cathodes for Li-ion batteries are comprehensively reviewed in this paper.

Emerging single-atom catalysts (SACs) and their applications in Li–air batteries, material design, reaction mechanism, and electrochemical performance are summarized. The future development of SACs and metal–air battery applications are also discussed.

Materials with synchronous capabilities of color change and actuation have prospects for application in biomimetic dual-stealth camouflage and artificial intelligence. However, color/shape dual-responsive devices involve stimuli that are difficult to control such as gas, light or magnetism, and the devices show poor coordination. Here, a flexible composite film with electrochromic/actuating (238° bending angle) dual-responsive phenomena, excellent reversibility, high synchronization, and fast response speed (< 5 s) utilizes a single active component, W₁₈O₄₉ nanowires. From in situ synchrotron X-ray diffraction, first principles calculations/numerical simulations, and a series of control experiments, the actuating mechanism for macroscopic deformation is elucidated as pseudocapacitance-based reversible lattice contraction/recovery of W₁₈O₄₉ nanowires (i.e. nanostructure change at the atomic level) during lithium ion intercalation/de-intercalation. In addition, we demonstrate the W₁₈O₄₉ nanowires in a solid-state ionic polymer-metal composite actuator that operates stably in air with a significant pseudocapacitive actuation.