The K-doped Li1-xKxFePO4 (x = 0, 0.005, 0.01, and 0.02) samples were synthesized successfully via a solid-state method, and the electronic structures of the samples were calculated by the first-principles based on density functional theory. Theoretical calculations show that the bandwidth of Li1-xKxFePO4 decreases with the increase in K+ doping, which is consistent with the experimental results. It was demonstrated that Li0.995K0.005FePO4 delivers higher capacity retention with 92.7% after 100 cycles compared with LiFePO4 (86.3%) at 1 C and shows better high-rate performance with capacities of...
