The effect of K-Ion on the electrochemical performance of spinel LiMn₂O₄

Spinel LiMn₂O₄ is regarded as one of the cathode active materials for rechargeable lithium-ion batteries with the most potential. K⁺-ion modified LiMn₂O₄ samples are synthesized by solid-state reaction. The SEM analysis shows that the modified samples exhibit uniform particle size distribution and much better crystallinity. The modified sample K1 exhibits ionic diffusion coefficient of 1.43 × 10^-10 cm^-2 s^-1 and 2.04 × 10^-10 cm^-2 s^-1, which is much higher than that of the un-modified spinel LiMn₂O₄ sample. The electrochemical measurements show that K⁺-ion modification could effectively reduce the charge transfer resistance, improve the capacity retention and rate capacity of the spinel materials.