Abstract: The conversion of spent lithium iron phosphate (LiFePO₄, LFP) batteries into photo-Fenton catalysts is an effective method to improve the economic benefits of recycling low-value batteries. In this study, the LFP cathode material was fully utilised to prepare a carbon network as a skeleton, and the iron phosphate-ferric oxalate-carbon composite (FPC-C) was synthesised by hydrothermal calcination of oxalic acid, while recovering more than 97% of Li and Al. The synthesized FPC-C had good photo-Fenton catalytic performance and stability, and the removal rate of reactive blue 4 reached 97% within 15 min, and the removal rate remained at 80% after five consecutive cycles. The removal rate remained above 80% after 5 cycles and had excellent degradation effects on common organic pollutants (all > 90%). The FPC-C material was shown to be loose and porous, and the adsorption rate of pollutants was increased from 6% to 27% compared to the unmodified material. The carbon network framework provided a strong electron transfer capacity for the reaction system, which facilitated the cycling of iron ions and accelerated the Fenton reaction rate. The oxalate improved the light absorption capacity of the material and enhanced the photocatalytic reaction effect. This study provides a feasible strategy for the resourceful recycling of spent LFP batteries.