This review paper examines the second life of Li-ion batteries, its market size, use cases, economics, and environmental impact, with a focus on the Indian context. The study highlights the increasing demand for sustainable energy storage solutions and the projected growth of the second-life battery market. It explores the various applications of second-life batteries, including grid-scale energy storage, residential energy storage, EV charging stations, and telecommunications backup power. The paper discusses the economic benefits of repurposing batteries, such as cost savings compared to new battery systems, and the factors influencing the economics of second-life Li-ion batteries. Furthermore, it emphasizes the importance of government policies and regulations that promote the reuse of batteries, with specific reference to initiatives in India. The environmental impact of second-life batteries is examined, including the reduction in raw material extraction, decreased energy consumption and greenhouse gas emissions during battery production, and the alleviation of waste generated from battery disposal. The challenges in recycling and disposal at the end of the battery's second life are also addressed, emphasizing the need for effective recycling technologies and infrastructure. The paper concludes by highlighting the opportunities for innovation, research, and collaboration in the second-life battery ecosystem, with a call for partnerships among stakeholders to drive advancements in battery management systems, repurposing technologies, and battery chemistry. The findings of this paper contribute to the understanding of the second-life battery industry in the Indian context and provide insights into its potential for sustainable energy storage and resource management.