STORAGE TECHNOLOGIES FOR SOLAR ENERGY: LITHIUM-ION BATTERIES VERSUS ALTERNATIVE

ABSTRACT
The growing share of photovoltaic generation in the electricity mix makes storage a key element for reliability, cost and operational safety. This article conducts an integrative review of nine studies (2020–2024) comparing lithium-ion (Li-ion) batteries to technological alternatives applicable to solar systems, including sodium-ion, vanadium redox flow batteries (VRFB), thermal storage in salts, and compressed air (CAES). The objective is to identify advantages and limitations of each solution in terms of energy efficiency, useful life/cycles, costs (LCOS), safety and adequacy by duration (short 1–4 h; medium 4–12 h; long >12 h). The search and selection resulted in a deliberate portfolio that was consistent with the thematic scope, based on peer-reviewed journals. Studies indicate that Li-ion remains the benchmark for residential/commercial applications and daily commutes of 2–6 h; VRFB stands out for high cyclic life and duration scalability; Na-ion emerges as a low-cost option with abundant materials; Thermal storage and CAES gain value in extended windows and scaled projects. It is concluded that the optimal choice depends on the coupling between dispatch window, degradation profile and security/supply requirements, and a combined technological matrix in PV+Storage systems is recommended.