The increased adoption of electric vehicles (EVs) generated a growing quantity of retired lithium-ion batteries, with concerns over disposal and the environment. Repurposing the batteries for energy storage and other applications presents a sustainable solution. A number of technical, economic, and regulatory hurdles, however, hinder the extensive adoption. The work in this paper examines battery aging, performance limits, repurposing challenges, and second-life applications for EV batteries. A mixed research strategy is applied, incorporating literature review, data evaluation, and assessment of the case study to examine trends in battery aging, capacity retention, energy efficiency, and concerns in the context of safety. The economic feasibility as well as the environmental feasibility is also examined to assess the feasibility of second-life application. The outcome shows the most prominent technical hurdles in the shape of non-uniform battery performance, risks with respect to safety, and the lack of standardization. A number of prospective solutions in the shape of advanced battery management systems, refurbishment process optimization, and upgraded state-of-health estimation procedures are proposed. By overcoming the hurdles, the efficiency as well as the sustainability of second-life EV batteries can be fostered, resulting in a circular battery economy and global efforts towards sustainable living.