Anode materials are an essential part of lithium-ion batteries (LIBs), which determine the performance and safety of LIBs. Currently, graphite, as the anode material of commercial LIBs, is limited by its low theoretical capacity of 372 mA·h·g^?1, thus hindering further development toward high-capacity and large-scale applications. Alkaline earth metal iron-based oxides are considered a promising candidate to replace graphite because of their low preparation cost, good thermal stability, superior stability, and high electrochemical performance. Nonetheless, many issues and challenges remain to be addressed. Herein, we systematically summarize the research progress of alkaline earth metal iron-based oxides as LIB anodes. Meanwhile, the material and structural properties, synthesis methods, electrochemical reaction mechanisms, and improvement strategies are introduced. Finally, existing challenges and future research directions are discussed to accelerate their practical application in commercial LIBs.

Halide perovskite light-emitting electrochemical cells are a novel type of the perovskite optoelectronic devices that differs from the perovskite light-emitting diodes by a simple monolayered architecture. Here, we develop a perovskite electrochemical cell both for light emission and detection, where the active layer consists of a composite material made of halide perovskite microcrystals, polymer support matrix, and added mobile ions. The perovskite electrochemical cell of CsPbBr₃:PEO:LiTFSI composition, emitting light at the wavelength of 523 nm, yields the luminance more than 7000 cd/m² and electroluminescence efficiency of 1.3×10⁵ lm/W. The device fabricated on a silicon substrate with transparent single-walled carbon nanotube film as a top contact exhibits 40% lower Joule heating compared to the perovskite optoelectronic devices fabricated on conventional ITO/glass substrates. Moreover, the device operates as a photodetector with a sensitivity up to 0.75 A/W, specific detectivity of 8.56×10¹¹ Jones, and linear dynamic range of 48 dB. The technological potential of such a device is proven by demonstration of 24-pixel indicator display as well as by successful device miniaturization by creation of electroluminescent images with the smallest features less than 50 μm.