One-Step Microwave Synthesis of Micro/Nanoscale LiFePO4/Graphene Cathode With High Performance for Lithium-Ion Batteries

Abstract

In this study, micro/nanoscale LiFePO 4 /graphene composites are synthesized successfully using a one-step microwave heating method. One-step microwave heating can simplify the reduction step of graphene oxide and provide a convenient, economical, and effective method of preparing graphene composites. The structural analysis shows that LiFePO 4 /graphene has high phase purity and crystallinity. The morphological analysis shows that LiFePO 4 /graphene microspheres and micron blocks are composed of densely aggregated nanoparticles; the nanoparticle size can shorten the diffusion path of lithium ions and thus increase the lithium-ion diffusion rate. Additionally, the graphene sheets can provide a rapid transport path for electrons, thus increasing the electronic conductivity of the material. Furthermore, the nanoparticles being packed into the micron graphene sheets can ensure stability in the electrolyte during charging and discharging. Raman analysis reveals that the graphene has a high degree of graphitization. Electrochemical analysis shows that the LiFePO 4 /graphene has an excellent capacity, high rate performance, and cycle stability. The discharge capacities are 166.3, 156.1, 143.0, 132.4, and 120.9 mAh g −1 at rates of 0.1, 1, 3, 5, and 10 C, respectively. The superior electrochemical performance can be ascribed to the synergy of the shorter lithium-ion diffusion path achieved by LiFePO 4 nanoparticles and the conductive networks of graphene.

Microwave as a Tool for Synthesis of Carbon-Based Electrodes for Energy Storage

“…For example, an advanced composite cathode material has been reported, consisting of LiFePO 4 and graphene. 120 For the synthesis, the precursor materials were heated in a MW oven for 10 min at a power of 1500 W. The incorporation of nanoparticles shortened the transport pathway of Li + ions and enhanced the diffusion of Li + ions into the pores of the material. Moreover, the nanoparticles enclosed by the conductive graphene sheets increased the stability of the electrode during continuous charge/discharge cycles.…”

“…However, graphene materials have also been investigated as LiB cathodes in combination with Li-based mixed metal oxides. For example, an advanced composite cathode material has been reported, consisting of LiFePO 4 and graphene . For the synthesis, the precursor materials were heated in a MW oven for 10 min at a power of 1500 W. The incorporation of nanoparticles shortened the transport pathway of Li + ions and enhanced the diffusion of Li + ions into the pores of the material.…”

All-Solid-State Lithium Ion Batteries Using Self-Organized TiO2 Nanotubes Grown from Ti-6Al-4V Alloy

“…Compared to many other cathode compositions, LiFePO 4 has a lower voltage of 3.45 V versus Li/Li + . However, LiFePO 4 shows flat charge-discharge curves during the two-phase Li insertion-extraction process and excellent cycling stability due to its unique ordered olivine structure [43]. The electrochemical reactions of LiFePO 4 with Li using a polymer electrolyte have been studied by cyclic voltammetry.…”

Study and Analysis of Removing the Carbon Deposition on the Inner Surface of a Turbo-Shaft by Chemically Assisted Magnetic Grinding

“…The surfactants rise to the interface and reduce the adhesion between grease and metal via oriented absorption. By a series of actions, such as madefaction, emulsification, dispersion, and solubilization, combining physical ways, such as heating, scrubbing, flushing, and ultrasonic wave, the dirt can be more quickly removed and dispersed into the detergent from the workpiece (Stancu et al, 2016;Liu et al, 2020).…”