On the electrochemical behavior of LiM XFe 1 − XPO 4 [M = Cu, Sn; X = 0.02] anodes – An approach to enhance the anode performance of LiFePO 4 material

Abstract

An attempt, for the first time, has been made to explore the possible electrochemical activity of partially substituted LiFePO 4 as negative electrode for lithium battery applications. In this regard, cationic substitution of Cu and Sn to the native LiFePO 4/C electroactive material has been made individually via. ball milling treatment. This simple procedure has resulted in the formation of metal substituted LiFePO 4 powders of phase pure nature and finer crystallite size (<1 μm) with better distribution of particles. Herein, 2% of metals such as Cu (transition) and Sn (non-transition) were chosen as dopants with a view to understand the effect of transition and non-transition metals upon LiFePO 4 individually. It is interesting to note that irrespective of the nature of the dopant metal, the simple route of cationic substitution via. ball milling endowed with improved conductivity of LiFePO 4, as evidenced by the augmented reversible specific capacity values of substituted LiFePO 4 anodes. In other words, the LiCu 0.02Fe 0.98PO 4/C anode delivered a reversible capacity of ∼380 mAh/g with an enhancement in the capacity retention behavior and excellent coulumbic efficiency value compared to that of LiFePO 4. In contrast, LiSn 0.02Fe 0.98PO 4/C anode displayed an appreciable reversible capacity of ∼400 mAh/g with a significant steady discharge profile. Results of Fourier Transform Infra Red (FTIR) spectroscopy and Cyclic Voltammetric studies of LiM X Fe 1 − X PO 4 (M = Cu, Sn)/C composites are also appended and correlated suitably.