LiMnPO₄ based phospho olivines are considered to be environmentally friendly, and low cost potential cathode material for the next generation of Li-ion secondary batteries to meet the huge market of electric and hybrid vehicles [1, 2]. The relatively higher operation voltage at around 4 V makes the theoretical specific energy of LiMnPO₄ (684 Wh/kg) 20% greater than that of LiFePO₄ (578 Wh/kg) while still compatible with most conventional electrolytes [3]. However, due to the low electrical conductivity and poor Li ion diffusion kinetics these materials are unsuitable for practical applications [4]. In here, carbon coated LiMnPO₄ was synthesized by both solid state and modified sol-gel technique using a low temperature synthesis techniques. The cathode materials obtained were characterized and performance was compared and evaluated. Results of the electrochemical tests show that the prepared LiMnPO₄/C (around 10 wt. % carbon) composites by both the routes exhibits not only a high initial discharge capacity but also good cycling stability. Although highly crystalline phase pure cathode materials could be obtained by both the processes, the materials prepared by sol-gel process delivered slightly better electrochemical performance when compared to solid state process.

References:

[1] C. Delacourt, P. Poizot, M. Morcrette, J. M. Tarascon and

C. Masquelier, Chem. Mater., 2004, 16, 93.

[2] J. Xiao, W. Xu, D. Choi and J.-G. Zhang, J. Electrochem. Soc.,

2010, 157, A142.

[3] Xiao, Jie, et al. Physical Chemistry Chemical Physics 13.40 (2011): 18099-18106.

[4] J. Yang, J.J, Journal of The Electrochemical Society 153 (4) (2006) A716–A723