Electrochemical energy storage is a key element of systems in a wide range of sectors, such as electro-mobility, portable devices, or renewable energy. The energy storage systems (ESS) considered here are batteries, supercapacitors, or hybrid components such lithium-ion capacitors. The durability of ESS determines the total cost of ownership and the global impacts (life cycle) on a large portion of these applications and thus their viability. Understanding ESS aging is a key issue for optimizing their design and usage within their applications. Knowledge of ESS aging is also essential for improving their dependability (reliability, availability, maintainability, and safety). In this Special Issue, we are looking for contributions helping to understand the aging mechanisms, modes, and factors for performing ESS diagnosis and prognosis, as well as innovative solutions for prolonging their lifespans. Topics of interest include, but are not limited to: Innovative measurement techniques of ESS aging; ESS aging modeling; ESS state-of-health (SOH) estimation; ESS prognostic and health management; Balancing circuits with consideration of the lifetime of ESS; Energy management laws taking into account aging; Influence of aging on cost and environmental impact of ESS; Multi-objective optimization strategies of ESS including aging consideration; Optimal sizing and design of ESS with respect to their lifetime.