Synthesis of LiFe0.4Mn0.6−x Ni x PO4/C by co-precipitation method and its electrochemical performances

Abstract

LiFe 0.4 Mn 0.6-x Ni x PO 4 /C(x = 0, 0.05, 0.1, and 0.2) composite cathode materials for lithium ion batteries have been prepared by the co-precipitation method using oxalic acid as a precipitator. The structure and morphology of precursors and products have been investigated. Electrochemical tests demonstrate that LiFe 0.4 Mn 0.55 Ni 0.05 PO 4 can deliver a specific capacity of 142 mAh g -1 at 0.1 C, and retains 133 mAh g -1 after 60 cycles. The rate performance of LiFe 0.4 Mn 0.6 PO 4 is obviously improved by doping Ni. The capacity of LiFe 0.4 Mn 0.55 Ni 0.05 PO 4 at 2 C is 110 mAh g -1 .

Understanding the Role of Solution Equilibrium and Precipitation Rate on Precursor Composition for Lithium-ion Battery Active Materials

“…While this study suggests that predictive calculations should be done to adjust the feed stoichiometry to target the desired precipitate stoichiometry, this is rarely reported. Of the 150 co-precipitation papers cited from the recent literature above, only 6 performed equilibrium calculations as part of their analysis 68,[81][82][83][84][85] , none used this analysis to guide their feed conditions, only some confirmed the stoichiometry of the transition metals in the precipitate 68,71,73,74,[86][87][88][89][89][90][91][92][93][94][95] , and none considered whether the relative rate of co-precipitation was different for the different transition metals. In this paper, we will use equilibrium calculations to guide the selection of feed conditions to achieve precursors with explicit composition control and will demonstrate the importance of such control for some solution conditions and impact on the electrochemical behavior of an exemplar cathode material.…”