As a new member of two-dimensional (2D) materials family, 2D transition metal borides (MBenes) have attracted rising attention owing to the remarkable thermodynamic stability, electrical and mechanical properties. Over the past several years, the study of MBenes has been extended from theoretical simulations to experimental applications, stimulated by the increasing synthesis methods of MBenes. However, the recent experimental applications about MBenes have not been comprehensively introduced. This review concentrates on a comprehensive overview of MBenes which have accordion-like structures derived from multilayer MAB phases and their relevant experimental progress. First, the concept of MBenes, development progress, structural, basic properties are introduced. Then synthetic routes for the production of MBens, including alkaline/acid solution, dealloying, molten salt-assisted etching methods are surveyed. Subsequently, the introduction and analysis of the latest applications such as metal-ion batteries, metal-air batteries, photocatalysis, electrochemical catalysis, sensors, environmental technology, magnetism, lubrication are summarized. Finally, perspectives and challenges for MBenes in synthesis and applications are briefly presented.

High-entropy ceramics (HECs) have attracted growing research attention since 2015, when the pioneering work on entropy-stabilized oxides was first reported. Derived from the definition of high-entropy alloys, HECs initially referred to disordered ceramic solid solutions comprising five or more principal elements in equimolar ratios occupying the same Wyckoff sites. The concept has rapidly evolved to encompass more complex systems with tunable element distributions across multiple crystallographic positions. Distinct from conventional ceramics, HECs are characterized by their unique chemical diversity and high configurational entropy, which contribute to enhanced structural stability and promising functional properties. Given the remarkable progress of HECs, this review systematically summarizes advancements over the past five years, including oxides (both simple and complex) and non-oxides (carbides, borides, and related compounds). Specifically, we focus on theoretical design principles for stability prediction and property optimization. We then examine the expanding compositional and structural space of emerging compounds and also discuss structure-property correlations and innovative processing methods. Furthermore, we provide a comprehensive overview of the most extensively investigated properties, including mechanical, thermal, electrical, catalytic, magnetic and dielectric characteristics. Looking forward, HECs hold great promise for various applications, and this review may provide some fundamental insights and practical design strategies for realizing their full potential.

With the advancement of hypersonic vehicles, extreme high temperature environments have imposed increasingly stringent requirements on the performance of thermal protection systems. Consequently, the development of high-performance thermal protection materials capable of withstanding extreme conditions has become a primary focus of current research. Ultra-high temperature ceramics (UHTCs) and their composites, known for their excellent oxidation resistance and ablation performance, are regarded as highly promising non-ablative thermal protection materials. This paper provides a systematic review of recent research progress on UHTC composites in several key areas, including innovations and optimizations in fabrication processes, exploration of toughening strategies and mechanisms, in-depth studies on oxidation and ablation resistance mechanisms, and the development and potential applications of high-entropy ceramics. Furthermore, the paper discusses the practical application prospects of UHTCs and their composites in extreme environments, analyzes the current technical challenges, and proposes future research directions and priorities.