3D Printed PEKK-derived, laser-induced graphene anodes for −20 to 50 °C operation in recyclable LMFP batteries

A schematic illustration of the pouch cell formation process from the PEKK filament is shown. The exceptional conductivity and mechanical integrity make graphene a promising anode material for lithium-ion batteries (LIBs), but scalable fabrication remains a significant challenge. We present a direct laser-induced graphitization method for converting poly(ether ketone ketone) (PEKK) into three-dimensional porous graphene (LIG-PEKK) under an argon atmosphere. The resulting LIG-PEKK (argon) features enhanced graphitization, interconnected mesoporosity, and superior Li + transport compared to air-processed counterparts. In full cells with LMFP/C cathodes, the argon-processed anode exhibits a reversible capacity of ∼163.8 mAh/g at C/8, retaining 90% capacity after 200 cycles. XPS and XRF quantification confirm minimal Fe/Mn dissolution and a stable LiF- and carbonate-rich solid-electrolyte interphase (SEI), with significantly lower transition-metal deposition (∼30% lower Fe, ∼20%–25% lower Mn) on the anode compared to air-processed cells. Temperature-dependent cycling from 50 to −20 °C reveals superior cold tolerance and reversible capacity recovery upon temperature normalization. Notably, the argon-processed LIG-PEKK anode demonstrates robust performance under mechanical abuse, as shown by nail-penetration infrared thermography, which indicates a minimal temperature rise (