How to make lithium iron phosphate better: a review exploring classical modification approaches in-depth and proposing future optimization methods

Abstract

This review discusses optimization methods for LiFePO4from the extent of electron and Li+migration and proposes two future optimization approaches.

Solvothermal water-diethylene glycol synthesis of LiCoPO4and effects of surface treatments on lithium battery performance

“…[13][14][15] The olivine-structured LiMPO 4 (M ¼ Fe, Mn, Co, Ni) phases have been intensively investigated as cathode materials for LIBs, [15][16][17][18] especially LiFePO 4 which has been successfully commercialised. [19][20][21][22][23][24] LiCoPO 4 has also attracted signicant attention due to its high redox potential (4.8 V vs. Li/Li + ) and high theoretical capacity (167 mA h g À1 ), making it a promising future cathode material for high-voltage LIBs. [25][26][27][28][29][30] However, use of LiCoPO 4 as a cathode in practical applications has been hindered by its unsatisfactory cycle stability and rate capability, which could be mainly attributed to its low electronic conductivity 17,[31][32][33][34][35][36] and poor Li + ionic conductivity [36][37][38][39][40][41] relating to the one-dimensional ion transport channels, 42 as well as to the decomposition of electrolytes under high potentials.…”

Non-stoichiometric carbon-coated LiFexPO4as cathode materials for high-performance Li-ion batteries

“…Lithium iron phosphate, with the characteristics of high theoretical capacity, inexpensive cost, environmental benignity and safety, [1][2][3] except for low electronic conductivity and ionic diffusivity, 4,5 has attracted much attention as a promising cathode material for Li-ion batteries. 6,7 Numerous strategies have been adopted to overcome the intrinsic drawbacks of lithium iron phosphate (LiFePO 4 ), involving surface modication with conductive agents, [8][9][10] decreasing the particles to nanometer sizes, [11][12][13] doping with supervalent ions, [14][15][16] etc.…”

The use of Raman and XPS spectroscopy to study the cathode material of LiFePO4/C

“…One of the main ways of increasing the electronic and ionic conductivity is coating the LiFePO4 particles with an electrically conductive addition and reducing the diffusion path of lithium ions by the synthesis of LiFePO4 nanocrystals. 1,2 The most commonly used component to date is carbon and its modifications. The main role of the carbon coating is to increase the surface electronic conductivity of powder nanocrystals, which makes it possible to fully use LiFePO4 active mass.…”

“…For an amorphous product, annealing is carried out longer (for ~12 h), for its goal in this case is not only to obtain a carbon phase, but also to form a crystal structure. [1][2][3][4] The paper present results of investigating lithium iron(II) phosphate, which has been synthesized in an ionic liquid of the composition choline chloride/diethylene glycol, and a carbon composite based on it. To investigate the carbon coating of LiFePO4/С and the effect of the high-temperature annealing stage on LiFePO4 (assess possible iron oxidation), Raman spectroscopy and X-ray photoelection spectroscopy (XPS) were used.…”