Our analysis reveals that Ni-based batteries surpassed lead-acid technologies in past generations, while current-generation lithium-ion (LiFePO 4, LiNiMnCoO 2) cells dominate, with energy densities up to 220 Wh/kg and cycle lives exceeding 2000 cycles. Pumped Hydro Storage, which utilizes gravitational potential energy, 2. LITHIUM-ION BATTERIES: This technology has reached a significant level of advancement and acceptance. In 2025, 108 GW of new battery storage capacity was deployed worldwide, 40% more than in 2024. Lithium‑iron phosphate (LFP) batteries now account for around 90% of deployments;. In the power sector, battery storage is the fastest growing clean energy technology on the market.