Carbon-based nanocomposites (CNCs) have emerged as transformative materials in battery technologies, offering significant enhancements in energy density, cycle stability, and conductivity. This chapter explores the role of CNCs in various battery chemistries, such as lithium-ion, sodium-ion, and zinc-air batteries, emphasizing their ability to improve charge/discharge efficiency and mitigate capacity fading. The environmental and economic advantages of CNCs are highlighted, including reduced dependence on scarce metals and improved lifecycle sustainability. Additionally, the scalability and technical challenges associated with the synthesis and integration of CNCs into existing technologies are discussed. Future directions focus on novel synthesis techniques, multifunctional applications, and expanding CNC usage to next-generation energy storage systems. This review concludes that CNCs hold immense potential in advancing sustainable battery technologies, paving the way for cleaner, more efficient energy solutions.