LiFePO4/C nanoparticle with fast ion/electron transfer capability obtained by adjusting pH values

Wang

ACS Appl. Mater. Interfaces

et al. 2022

A fluoride-ion battery (FIB) is a novel type of energy storage system that has a higher volumetric energy density and low cost. However, the high working temperature (>150 °C) and unsatisfactory cycling performance of cathode materials are not favorable for their practical application. Herein, fluoride ion-intercalated CoFe layered double hydroxide (LDH) (CoFe-F LDH) was prepared by a facile co-precipitation approach combined with ion-exchange. The CoFe-F LDH shows a reversible capacity of ∼50 mAh g–1 after 100 cycles at room temperature. Although there is still a big gap between FIBs and lithium-ion batteries, the CoFe-F LDH is superior to most cathode materials for FIBs. Another important advantage of CoFe-F LDH FIBs is that they can work at room temperature, which has been rarely achieved in previous reports. The superior performance stems from the unique topochemical transformation property and small volume change (∼0.82%) of LDH in electrochemical cycles. Such a tiny volume change makes LDH a zero-strain cathode material for FIBs. The 2D diffusion pathways and weak interaction between fluoride ions and host layers facilitate the de/intercalation of fluoride ions, accompanied by the chemical state changes of Co2+/Co3+ and Fe2+/Fe3+ couples. First-principles calculations also reveal a low F– diffusion barrier during the cyclic process. These findings expand the application field of LDH materials and propose a novel avenue for the designs of cathode materials toward room-temperature FIBs.

Section: Resultssupporting

confidence: 64%

A Zero-Strain Insertion Cathode Material for Room-Temperature Fluoride-Ion Batteries

Wang

ACS Appl. Mater. Interfaces

et al. 2022

“…The homogeneous spindle-shaped particles are usually attributed to the chelation effect of EG and the weak acidic environment provided by ascorbic acid [18]. The finer particles have a positive effect on the modification of the cathode material, which will not only providing sufficient reaction sites, the conductive ability will also be enhanced along with the shortening of the diffusion distance of ions in the material [19][20][21].…”

Section: Resultsmentioning

confidence: 99%

Synthesis and modification mechanism of vanadium oxide coated LiFePO₄ cathode materials with excellent electrochemical performance

Geng,

Zou,

Wang

et al. 2023

Nanotechnology

In an era of rapid industrial development, such that the demand for energy is increasing daily, lithium-ion batteries (LiBs) are playing a dominant role in energy storage devices due to their high safety and low cost. However, it is still a challenge for the preparation of advanced cathodes, which can determine the battery performance, with stable structures and fast diffusion of Li+. This is especially the case for lithium iron phosphate (LFP), a cathode material with severe limitations due to its low conductive efficiency. To improve its conductivity, LFP was compounded with defect-modified V2O5to prepare LFP/V/C materials with excellent electrochemical properties, which exhibited an initial capacity of 138.85 mAh/g and 95% retention after 500 charge/discharge cycles at a current density of 5C. Also, the effect of defects on ionic diffusion was discussed in detail by means of DFT calculations, confirming that the improvement of electrochemical performance is closely related to the introduction of hybrid conductive layers of surface cladding. Key Words: Lithium iron phosphate; Vanadium oxide; Lithium-ion battery; Solvothermal.

“…45 degrees, corresponding to the charge-transfer reaction and the Li-ion diffusion, respectively. Figure 1(e) shows the equivalent circuit used for fitting and analyzing the Nyquist plots obtained [30]. The resistance R s and R ct are ascribed to solution and charge transfer resistance, respectively.…”

Section: Experimental Methods and Measurementsmentioning

confidence: 99%

Physics based modeling of LiFePO₄ cathodes: effects of electrode parameters on cell performance during fast charging

Aakanksha,

Sahoo,

Sharma

et al. 2023

J. Phys. Energy

Lithium-iron phosphate (LFP) has emerged as a potential cathode material due to its lower cost and higher stabilities. This work investigates LFP cell behavior at higher C-rates via a detailed simulation study. To facilitate this investigation, a physics-based electrochemical model is calibrated and validated with in-house experimental data. The validated model is used to study the effect of particle size, lithium diffusivity, and electrode thickness on the charge-discharge capacity of Li-LFP cells for a range of C-rates up to 5 C. A detailed discussion is carried out to explain the results of parametric studies, in terms of transport limitations, irreversible losses (overpotentials) and their dependence on different electrode parameters. The model helps us to depict the effect of these parameters on internal profiles of SOC and overpotentials, allowing for a deeper understanding of the cell behavior. Overall, the simulations show that the LFP cell is able to exhibit good capacity at higher C-rates by tuning the particle size and lithium diffusivity. An optimal combination of material and physical parameters is identified to maximize the possible capacity of LFP electrodes.