This review explores the role of bidirectional charging in enhancing grid stability and flexibility through Vehicle-to-Everything (V2X) applications, while addressing battery degradation concerns. The study examines the impact of EV charging patterns on battery longevity and evaluates advanced aging-aware optimization algorithms for bidirectional charging. It highlights the potential of EVs as dynamic energy storage systems, contributing to grid demand management and renewable energy integration. The paper discusses various V2X applications, including Vehicle-to-Grid (V2G), Vehicle-to-Microgrid (V2M), Vehicle-to-Home/Building (V2H/V2B), and Vehicle-to-Load (V2L), emphasizing their benefits and challenges. It also addresses the technical and operational complexities of bidirectional charging, including the need for infrastructure upgrades, regulatory frameworks, and cybersecurity measures. The study presents case studies of real-world bidirectional charging projects and programs, demonstrating their economic and grid benefits. It further analyzes battery aging mechanisms, such as capacity fade and power fade, and their impact on battery performance. The paper proposes aging-aware optimization strategies to mitigate battery degradation, including the use of machine learning and reinforcement learning techniques. The findings underscore the importance of balancing EV charging and discharging to maximize battery life while ensuring grid stability. The study concludes that bidirectional charging has significant potential to support the transition to a sustainable, resilient, and efficient energy system, but requires continued research and development to address the challenges associated with battery degradation and grid integration.This review explores the role of bidirectional charging in enhancing grid stability and flexibility through Vehicle-to-Everything (V2X) applications, while addressing battery degradation concerns. The study examines the impact of EV charging patterns on battery longevity and evaluates advanced aging-aware optimization algorithms for bidirectional charging. It highlights the potential of EVs as dynamic energy storage systems, contributing to grid demand management and renewable energy integration. The paper discusses various V2X applications, including Vehicle-to-Grid (V2G), Vehicle-to-Microgrid (V2M), Vehicle-to-Home/Building (V2H/V2B), and Vehicle-to-Load (V2L), emphasizing their benefits and challenges. It also addresses the technical and operational complexities of bidirectional charging, including the need for infrastructure upgrades, regulatory frameworks, and cybersecurity measures. The study presents case studies of real-world bidirectional charging projects and programs, demonstrating their economic and grid benefits. It further analyzes battery aging mechanisms, such as capacity fade and power fade, and their impact on battery performance. The paper proposes aging-aware optimization strategies to mitigate battery degradation, including the use of machine learning and reinforcement learning techniques. The findings underscore the importance of balancing EV charging and discharging to maximize battery life while ensuring grid stability. The study concludes that bidirectional charging has significant potential to support the transition to a sustainable, resilient, and efficient energy system, but requires continued research and development to address the challenges associated with battery degradation and grid integration.