Recent advances in single device photoactive batteries

Single-device photoactive batteries (SPBs) represent an emerging paradigm that unifies solar energy conversion and electrochemical storage within a single compact system. Unlike conventional photovoltaic–battery hybrids that rely on external wiring or discrete energy modules, SPBs integrate light harvesting, charge separation, and ion transport directly into a monolithic configuration. This integration enables direct solar-to-chemical energy conversion, improving volumetric energy density and simplifying device design. Recent advances in photoactive materials, including halide perovskites, transition-metal oxides, and organic–inorganic hybrid systems have significantly expanded the possibilities for efficient and durable SPBs. Concurrently, innovations in electrode architectures, such as tandem-inspired multilayers, nanostructured scaffolds, and solid-state or flexible platforms, have improved charge management and structural resilience. This review systematically discusses recent developments in SPBs, emphasizing the interplay between materials chemistry, device architectures, photoelectrochemical performance, and stability mechanisms. Special attention is devoted to degradation pathways under illumination, bias, and environmental stress, alongside strategies for interfacial passivation, encapsulation, and electrolyte optimization. The review also identifies key scientific and engineering challenges, including the trade-off between photo-conversion efficiency and operational durability, the lack of standardized testing protocols, and the difficulty of scaling nanoscale architectures into manufacturable devices. Finally, perspectives are provided on future directions in materials design, interface engineering, and device integration. By bridging insights from photovoltaics, battery chemistry, and materials science, this work highlights a pathway toward stable, efficient, and scalable SPBs for next-generation autonomous and flexible energy systems.