Synergistic Mg and Zn dual-doping with carbon coating for advanced LiMn0.6Fe0.4PO4 cathode materials

LiMn x Fe 1 − x PO 4 (LMFP) is a promising cathode candidate due to its high working voltage, cost-effective advantages, and environmentally friendly characteristics. However, LMFP is constrained by issues such as low intrinsic electronic and ionic conductivity, as well as Jahn–Teller lattice distortion induced by Mn 3+ , which limit its practical performance. To synergistically optimize its electrochemical behavior, LiMn 0.6 − x − y Fe 0.4 Mg x Zn y PO 4 (x = 0, y = 0; x = 0.005, y = 0.005; x = 0.01, y = 0; x = 0, y = 0.01) composite materials were designed and synthesized via a solvothermal method in this study. A comparative investigation of these samples was conducted to systematically elucidate the mechanisms underlying individual Mg and Zn doping and their synergistic co-doping. The experimental results indicate that the synergistic strategy of Mg and Zn dual-doping combined with carbon coating helps stabilize the olivine structure of LMFP, improves the reaction kinetics, and lowers the Li + diffusion energy barrier. The optimized LMFP/C-MgZn1 exhibits enhanced electrochemical performance, retaining 92.42% of its capacity after 600 cycles at 1.0 C and delivering a discharge specific capacity of 109.8 mAh g −1 at 10.0 C. Furthermore, Density Functional Theory (DFT) calculations indicate that the co-doping strategy improves the reaction kinetics by reducing both the material’s band gap and the Li + diffusion energy barrier. Graphical abstract Mg Zn co doping stabilizes LMFP/C, reduces the Li diffusion barrier and band gap,and enables fast kinetics with durable cycling. The alternative text for this image may have been generated using AI.