Our research on unconventional energy harvesting, storage, and saving devices aims to provide sustainable and clean energy solutions. We developed stretchable energy harvesting systems and wearable energy storage devices suitable for integration with mobile electronics(^(ⅰ)Advanced Functional Materials, 2017). Furthermore, we introduced biocompatible and biodegradable batteries (^(ⅱ)Advanced Materials, 2021), specially designed for safe and long-term operation in human-friendly electronic systems. To improve the portability and practical usability of wearable and implantable electronics, we also developed a high-quality flexible thin-film battery utilizing a damage-free dry transfer method (^(M)Nature Materials, 2024). In addition, we developed transparent and colored photovoltaic devices for sustainable and distributed solar power generation (^(ⅲ)Nature Communications, 2022), and passive cooling devices for energy saving strategies (^(ⅳ)Advanced Materials, 2025)Collectively, these technologies represent a step forward in energy device technologies for a sustainable energy future.