The future of energy storage depends on pushing the limits. We need battery solutions with greater capacity, greater power potential, longer life, sustainability, and safety, and meeting the needs of today’s serious consumers. Lithium-ion batteries have become the first choice for grid-connected solar backup systems, and the reasons are easy to understand. However, with the advancement of technology, a new winner has emerged in the competition for energy storage solutions: lithium iron phosphate batteries (LiFePO4). The lithium iron phosphate technology (also known as LFP or LiFePO4) that appeared in 1996 is replacing other battery technologies due to its technical advantages and very high level of safety. Due to its high power density, this technology is used for medium-power traction applications (robots, AGVs, electric vehicles, last-mile delivery, etc.) or heavy traction applications (ship towing, industrial vehicles, etc.) The long service life of LFP and the possibility of deep cycling allow LiFePO4 to be used in energy storage applications (standalone applications, off-grid systems, battery self-consumption) or general fixed storage. Lithium iron phosphate uses similar chemical properties to lithium ions and uses iron as the cathode material. Compared with their lithium-ion counterparts, the advantages of LiFePo4 are many. Let us explore the many reasons why lithium iron phosphate batteries have become the future of solar storage.