High-performance Na-doped LiFePO4 cathode material derived from acid-washed iron red for the simultaneous immobilization of multi-metals

To immobilizing hazardous elements of metallurgical waste and meet the demand for cathode materials in lithium-ion battery industries, LiFePO4/C cathode material was successfully prepared via a simple carbothermal reduction method using acid-pickled iron oxide red as raw material by orthogonal tests. To further improve electrochemical performance, Na-doped LiFePO4/C cathode material designed with the first-principles calculation verification was synthesized by solid-state method at the optimal experimental conditions including the ball-milling medium of 3 h, the reaction temperature at 750 °C in heating rate of 5 °C·min−1 for 4 h. The results reveal that Na doping can effectively change the band gap structures and microstructure, which reduced the size of the particle and increased the electronic conductivity. The Li0.75Na0.25FePO4/C electrode showed a discharge capacity of 139.2 mAh·g−1 at 0.5 C and an excellent capacity retention of 98.9% after 50 cycles. The synergy strategy was a sustainable solution for immobilizing hazardous heavy metal elements, which paves a novel facile and cost-effective way towards high-performance LiFePO4 cathodes and promising markets for lithium-ion battery industries.