High-entropy ceramics: From paradigm formation to ordered development

High-entropy ceramics (HECs), defined as single-phase inorganic solid solutions comprising five or more principal elements in equimolar or near-equimolar ratios, have emerged as a frontier and hotspot in materials science over the past decade. Their expansive compositional space and diverse crystal structures open up new avenues for the design and performance regulation of ceramic materials. Initially focused on proving the feasibility of entropy-stabilized phases, the field rapidly expanded into a vast, complex landscape of non-equimolar, multi-anionic, and medium-entropy compositions. This exploratory “great chaos” successfully validated the concept across diverse ceramic families—oxides, carbides, borides, nitrides, silicides—and unlocked extraordinary properties, including ultra-high temperature stability, exceptional radiation tolerance, ultralow thermal conductivity, and superior energy storage density. The realization of performance-tailored HECs fundamentally depends on rational compositional design and precise control of preparation processes—core challenges that remain at the heart of current research. However, a clear “scissors gap” has emerged between the rapid accumulation of experimental data and the lag in theoretical frameworks and data comparability. This review synthesizes a decade of research to chart a crucial transition “from chaos to order.” It formulates emerging design paradigms for targeted applications such as oxidation-resistant ultra-high temperature ceramics, thermal barrier coatings, durable nuclear materials, and high-performance energy storage and conversation materials. The analysis highlights the shift from discovery to quantitative efforts integrating computational thermodynamics, advanced characterization, and machine learning. Despite remarkable progress, significant bottlenecks persist in processing, standardized characterization, and scaling from powder to component. The future roadmap emphasizes establishing robust structure-property relationships, fostering community-wide data standards, and advancing rational, physics- and AI-guided design to systematically realize the immense technological potential of HECs.