What role does phosphoric acid play in the lithium iron phosphate battery supply chain?

Phosphoric acid is the critical intermediate linking traditional phosphorus chemicals to the energy storage boom. Lithium iron phosphate (LFP) cathode production relies on iron phosphate, which is manufactured from either purified wet-process acid or thermal acid. The process route matters: iron-based methods require high-purity acid, typically thermal, yielding higher tap density and fewer impurities for premium power battery applications. Ammonium and sodium routes use lower-cost industrial-grade acid with trade-offs in performance. Producers with captive phosphate rock, iron sources, and acid capacity can cut costs by 1,000-2,000 yuan per ton versus merchant buyers. As LFP demand grows for EVs and storage, phosphorus chemical firms are pivoting capacity toward battery-grade acid and iron phosphate, with several announcing 100,000-ton-scale projects. This shift is re-rating traditional chemical companies as energy material suppliers.