Facile Synthesis and Electrochemical Performance of LiFePO₄/C Composites Using Fe–P Waste Slag

Abstract

A facile synthesis route has been developed to prepare LiFePO 4 /C composites by using Fe−P waste slag from the industrial production of yellow phosphorus. The processes included reclaiming Fe and P in the form of a ferroalloy, preheating the Fe−P with lithium salts, and complementary phosphorus source in air to produce a precursor, and calcining the precursor with glucose in Ar to obtain the products. The reaction process and electrochemical performance were investigated with various techniques. LiFePO 4 /C with 5.9 wt % carbon exhibits enhanced power capability, low polarization, high reaction activity and reversibility. The discharge capacities are 150, 147, 131, 124, 112, and 93 mAh/g at different current rates of 0.1, 0.2, 0.5, 1, 2, and 5 C, respectively. The recovery rate at 0.1 C is 98.9% after 130 cycles at the given rates. The results are comparable to that of the LiFePO 4 /C prepared using FePO 4 or other Fe salts, which indicates the applicability of the novel simple way put forward in this work to convert industrial waste into energy materials for scaling up based on low cost.

Effects of Solvents on the Electrochemical Performance of LiFePO4/C Composite Electrodes

“…Lithium metal was used as the anode, acting as the counter and reference electrode. Using the above various electrolytes, cells were assembled by sandwiching a Celgard 2300 microporous separator between the cathode and the anode in a glove box filled with dry argon gas …”

Comparisons of heat treatment on the electrochemical performance of different carbons for lithium-oxygen cells

“…EIS measurements of the fresh Li-O 2 cells were performed over a frequency range of 10 mHz ∼ 100 kHz with a sinusoidal excitation voltage amplitude of 10 mV on an electrochemical workstation consisting of the PAR273A and a signal recovery model 5210 lock-in-amplifier controlled by Powersuite software. The impedance curves were fitted using Zsimpwin and Zview software [40,41].…”

“…2d, and the theoretical impedance plots match exactly with the experimental curves. Considering the nonhomogeneity such as porosity, roughness and geometry in the electrode system, constant phase element (CPE) Q is used to substitute for capacitance C [17,40,41]. A depressed semicircle will be formed when the CPE is placed in parallel with a resistor, as shown in Fig.…”

“…The fitted results of the EIS curves are summarized in Table 2. The high R i , R ct and W values of CNTs and HT-CNTs may be from the complex microstructure, the electron jump between different layers and the long diffusion path because CNTs are made of many cylinder layers with a long length [17,21,39,41]. The low diffusion resistance of AC is from its developed microstructure with plenty of microchannels for gas transport.…”

Facile synthesis and electrochemical performances of secondary carbon-coated LiFePO4-C composite for Li-ion capacitors based on neutral aqueous electrolytes

“…There is an urgent need for the development of reliable green electrical energy storage (EES) technologies. Traditional EES devices are divided into two kinds: Li-ion batteries (LIBs) and supercapacitors [1,2]. However, the application of supercapacitors and LIBs are limited because of their low energy density and low power density, respectively.…”