This book offers a comprehensive overview of the latest advancements in energy materials, devices, and systems, presented at the 2nd International Conference on Advanced Energy Materials, Devices, and Systems (AEMDS 2025) in Kuala Lumpur, Malaysia, from September 18-20, 2025. The book highlights the growing global need for high-performance energy storage devices, with a particular focus on the materials essential for their development. AEMDS 2025 provides a platform for discussing groundbreaking experimental findings, ongoing progress, and practical applications in the field. Leading experts from the global energy sector deliver keynote and invited talks, fostering a dynamic exchange of ideas and enhancing our understanding of emerging energy materials and their diverse applications in research.