Immersed Halide Perovskite‐Based Electrochemical Cells for Stable Solar Water Splitting: Achievements, Opportunities, and Prospects

Abstract Recently, halide perovskite materials have attracted significant research interest in photoelectrochemical cells as promising photoabsorbers due to their superior optoelectronic properties. However, their instability under environmental conditions remains a major obstacle to the development of stable water‐splitting devices. This review thoroughly examines the growing array of encapsulation strategies that have accelerated the integration of perovskite materials into water‐splitting systems. In addition, various approaches to extending device lifetime while maintaining high performance are discussed in detail. Recent advances that render perovskite‐based water‐splitting systems a viable source of low‐cost green hydrogen are also highlighted. Finally, current scientific challenges, emerging concepts, and future research directions aimed at enhancing both the performance and operational stability of perovskite‐based electrochemical cells are introduced.