Ultra-High Density LiFePO 4 Electrodes

An ultra-high density LiFePO 4 electrode was fabricated using low surface area LiFePO 4 /carbon composite particles with a flake morphology (F-LFP). The electrode exhibited a high active loading of 17 mg cm −2 and a high active mass fraction of 96%. It was densified to a coating density exceeding 3.0 g cm −3 , corresponding to an active packing fraction of 85.6% and an electrode porosity of just 8.6%. In Li cells, this electrode achieved an energy density of 1670 Wh L −1 . To our knowledge, this is the highest active packing fraction and the highest energy density reported for a LiFePO 4 electrode, leading to a notable 28% increase in volumetric energy density compared to a conventional LFP electrode. Furthermore, the ultra-high density F-LFP electrode exhibited lower polarization, a 2-fold decrease in charge transfer resistance, and maintained comparable rate capability to conventional LFP, despite its highly densified structure. When paired with graphite in full cells, the F-LFP electrode demonstrated improved capacity retention and higher rate performance. These advancements could allow LiFePO 4 to be utilized in batteries for higher energy density applications.