Ameliorated Li+ extraction/insertion kinetics and stability of LiMnPO4 by Al3+ doping

Abstract

The effect of doping Al³⁺ into Li_1−xAl_xMnPO₄ is investigated by comparing the properties of LiMnPO₄ and Li_0.98Al_0.02MnPO₄ and their delithiated phases. Through the experiment of chemical delithiation and the measurements of potentiostatic intermittent titration technique (PITT) and chronoamperometry, it is found that doping Al³⁺ into LiMnPO₄ to obtain Li_0.98Al_0.02MnPO₄ can accelerate the kinetics of Li⁺ extraction/insertion, which improves the rate capability of LiMnPO₄. In addition, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry-differential scanning calorimetry (TG-DSC) measurements reveal that the Al³⁺ doping can also effectively ameliorate the stability of the delithiated phase of LiMnPO₄.