Synthesis, characterization and electrochemical performances of γ-Fe2O3 cathode material for Li-ion batteries

Abstract

Maghemite nanoparticles were successfully synthesized via a co-precipitation method and electrochemical-optical properties of three different sizes were studied. Using this material as a Li-ion battery cathode, the results of charge-discharge tests showed that decreasing the maghemite particle size increased the lithium hosting capacity. First discharge capacities for cathodes made of material of particle size 11 and 19 nm were 206 and 186 mAh g -1 respectively, while for micron-sized cathode material a discharge capacity of 26 mAh g -1 was obtained. Electrochemical impedance spectroscopy (EIS) was used to derive equivalent circuit elements, which confirmed a reduction in lithium insertion resistance for material with a smaller particle size. EIS investigations disclosed that the R ct and Z W reduced with reduction of particle size, which indicates cathode material with lower particle size is more suitable. Band-gaps of the materials were determined using the diffuse reflectance spectroscopy technique on the base of Kubelka-Munk theory. The results showed that the needed energy for electron conduction reduces with reduction of particle size, which results in capacity enhancement.

Synthesis of porous γ-Fe2O3 from scorodite synthesized using ultrasound irradiation and evaluation of its battery performance

“…Abbasi et al reported a discharge capacity of 114 mAh g −1 for a current density of 100 mA g −1 in the voltage range 1.5-4.0 V (versus Li/Li + ) (the current density in this experiment was 165-168 mA g −1 ). 19) Thus, the discharge capacities of all the maghemites obtained in this experiment were higher than the reported value. In addition, the BET value of the deposited porous maghemite becomes larger, the discharge capacity shows higher value.…”

“…18) γ-Fe 2 O 3 has been reported as a cathode material for lithiumion batteries and is gaining attention as one of the resource-rich iron-based materials. [18][19][20][21][22][23][24] The deposited clustered porous γ-Fe 2 O 3 was able to be charged and discharged as a cathode material for lithium-ion batteries. 16) In addition, porous maghemite produced from polyhedral scorodite particles (about 1 μm in diameter) showed potential as a cathode material.…”

Promoting Reversibility of Multielectron Redox in Alkali-Rich Sulfide Cathodes through Cryomilling

“…A lower mass transfer resistance suggests faster diffusion within the particle. We hypothesize that decreased crystallite size and increased microstrain from cryomilling contribute to shorter diffusion pathways for alkali metal deintercalation. − …”

Synthesis of porous γ-Fe2O3 via alkaline treatment of size controlled scorodite particles synthesized using ultrasound irradiation and its evaluation as a cathode for lithium-ion battery

“…20) Nanosized γ-Fe 2 O 3 has been studied as a potential cathode material for lithium-ion batteries. [21][22][23][24][25][26][27] γ-Fe 2 O 3 is an iron-based materials that is cheaper and more abundant than lithium cobalt oxide. The charge/discharge reaction of γ-Fe 2 O 3 when using cathode material is expressed according to the following reaction Charge…”