Synthesis of LiFePO4/graphene microspheres while avoiding restacking of graphene sheet’s for high-rate lithium-ion batteries

First-principles study of LiFePO4 modified by graphene and defective graphene oxide

The energy stability and electronic structural of graphene and defective graphene oxide (GO) parallel to the surface of LiFePO4 (010) were theoretically investigated by using first-principles density functional theory calculations within the DFT + U framework. The calculated formation energy shows that GO coating on the surface of LiFePO4 (010) is energetically favorable and has higher bond strength compared to graphene. The calculation of the electronic structure indicates that the emergence of band in-gap states originates from graphene coating, with adsorbed O atoms contributing significantly above the Fermi level. Electron density difference indicate that GO stands on the LFP (010) surface through C-O and Fe-O bonds, rather than relying on van der Waals forces placed parallel to the LFP crystal, with the chemical bond at the LFP/GO interface (Fe-O-C) both anchoring the coated carbon layer and promoting electron conductivity at the interface. In addition, LFP/GO shows superior electrochemical performance, Atomic Populations suggests that the average Fe-O bonding on the surface of LiFePO4 (010) was clearly changed after graphene or GO coating, which led to the expansion of Li+ channels and favored the migration insertion and extraction of Li+.

Spray-Drying of Electrode Materials for Lithium- and Sodium-Ion Batteries

The performance of electrode materials in lithium-ion (Li-ion), sodium-ion (Na-ion) and related batteries depends not only on their chemical composition but also on their microstructure. The choice of a synthesis method is therefore of paramount importance. Amongst the wide variety of synthesis or shaping routes reported for an ever-increasing panel of compositions, spray-drying stands out as a versatile tool offering demonstrated potential for up-scaling to industrial quantities. In this review, we provide an overview of the rapidly increasing literature including both spray-drying of solutions and spray-drying of suspensions. We focus, in particular, on the chemical aspects of the formulation of the solution/suspension to be spray-dried. We also consider the post-processing of the spray-dried precursors and the resulting morphologies of granules. The review references more than 300 publications in tables where entries are listed based on final compound composition, starting materials, sources of carbon etc.

Ultra sensitive detection of Cd (II) using reduced graphene oxide/carboxymethyl cellulose/glutathione modified electrode

The present work describes the electrochemical detection of Cd²⁺ using reduced graphene oxide (rGO), carboxymethyl cellulose (CMC) and glutathione (GSH) modified glassy carbon electrode (GCE) by Square Wave Anodic Stripping Voltammetry (SWASV). The prepared nanocomposite was characterized by X-ray diffraction (XRD), RAMAN, Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The influence of experimental parameters such as effect of pH, choice of supporting electrolyte, deposition time and deposition potential, were optimized. Under the optimized conditions, the linear relationship between the current intensity and Cd²⁺ concentration (2-20 nM) was I (μA) = -6.78 (c/nM) + 4.547 (R² = 0.996). The detection limit and sensitivity achieved for the modified electrode were 0.05 nM and 4.5 μA/nM respectively. Finally, rGO/CMC/GSH/GCE was successfully demonstrated for the detection of Cd²⁺ in real samples, and the results were compared with AAS analysis.