Vapor Deposition Engineering for Thin-Film Microbatteries: From Nanoscale Ionics to Interface-Integrated Architectures

The rapid proliferation of microelectronics, coupled with the advent of the internet of things (IoT) era, has created an urgent demand for miniaturized, integrable, and reliable on-chip energy storage systems. All-solid-state thin-film microbatteries (TFMBs), distinguished by their intrinsic safety, compact design, and compatibility with microfabrication techniques, have emerged as promising candidates to power next-generation IoT devices. Nevertheless, in contrast to the well-established development of conventional lithium-ion batteries, the advancement of TFMBs remains at an early stage, facing persistent challenges in materials innovation, interface optimization, and scalable manufacturing. This review critically examines the pivotal role of vapor deposition technologies, including magnetron sputtering, pulsed laser deposition, thermal/electron-beam evaporation, chemical vapor deposition, and atomic layer deposition, in the fabrication and performance modulation of TFMBs. We systematically summarize recent progress in thin-film electrodes and solid-state electrolytes, with particular emphasis on how deposition parameters dictate crystallinity, lattice orientation, and ionic transport in functional layers. Furthermore, we highlight strategies for solid-solid interface engineering, three-dimensional structural design, and multifunctional integration to enhance capacity retention, cycling stability, and interfacial compatibility. Looking ahead, TFMBs are expected to evolve toward multifunctional platforms, exhibiting mechanical flexibility, optical transparency, and hybrid energy-harvesting compatibility, thereby meeting the heterogeneous energy requirements of future IoT ecosystems. Overall, this review provides a comprehensive perspective on vapor-phase-enabled TFMB technologies, delivering both theoretical insights and technological guidelines for the scalable realization of high-performance microscale power sources.