Design of LiFePO4 and porous carbon composites with excellent High-Rate charging performance for Lithium-Ion secondary battery

Mass Transfer Analysis for Achieving High-Rate Lithium-Air Batteries

Lithium-air batteries (LABs) have aroused worldwide interest due to their high energy density as a promising next-generation battery technology. From a practical standpoint, one of the most pressing issues currently in LABs is their poor rate performance. Accelerating the mass transfer rate within LABs is a crucial aspect for enhancing their rate capability. In this Perspective, we have meticulously analyzed the ion and oxygen transport processes to provide readers with a comprehensive understanding of the mass transfer within LABs. Following this, we have discussed potential misconceptions in the existing literature and propose our recommendations for improving the rate performance of LABs. This Perspective provides a deep insight into the mass transfer process in LABs and offers promising strategies for developing other high-rate metal-O2 batteries.

Reduced Graphene Oxide Coating LiFePO4 Composite Cathodes for Advanced Lithium-Ion Battery Applications

Recently, the application of LiFePO4 (LFP) batteries in electric vehicles has attracted extensive attention from researchers. This work presents a composite of LFP particles trapped in reduced graphene oxide (rGO) nanosheets obtained through the high-temperature reduction strategy. The obtained LiFePO4/rGO composites indicate spherical morphology and uniform particles. As to the structure mode of the composite, LFP distributes in the interlayer structure of rGO, and the rGO evenly covers the surface of the particles. The LFP/rGO cathodes demonstrate a reversible specific capacity of 165 mA h g-1 and high coulombic efficiency at 0.2 C, excellent rate capacity (up to 10 C), outstanding long-term cycling stability (98%) after 1000 cycles at 5 C. The combined high electron conductivity of the layered rGO coating and uniform LFP particles contribute to the remarkable electrochemical performance of the LFP/rGO composite. The unique LFP/rGO cathode provides a potential application in high-power lithium-ion batteries.

Prominent enhancement of stability under high current density of LiFePO4-based multidimensional nanocarbon composite as cathode for lithium-ion batteries

A facile method for synthesizing carbon-coated lithium iron phosphate (LiFePO4, LFP) and an LFP-based multidimensional nanocarbon composite to enhance the electrochemical performance of lithium-ion batteries is presented herein. Three types of cathode materials are prepared: carbon-coated LFP (LC), carbon-coated LFP with carbon nanotubes (LC@C), and carbon-coated LFP with carbon nanotubes/graphene quantum dots (LC@CG). The electrochemical performances of the LC-nanocarbon composites are compared, and both LC@C and LC@CG show improved electrochemical performance than LC. Compared with both the LC and LC@C electrodes, the LC@CG electrode exhibits the highest specific capacity of 107.1 mA h g-1 under 20C of current density, as well as higher capacities and greater stability over all measured current densities. Moreover, after 300 charge-discharge cycles, the LC@CG electrode exhibits the best stability than the LC and LC@C electrodes. This is attributable to the graphene quantum dots, which enhance the morphological stability of the LC@CG electrode during electrochemical measurements. Our findings suggest that LFP-nanocarbon composites are promising as cathode materials and highlight the potential of graphene quantum dots for improving the stability of cathodes.

Gold-Based Nanostructures for Antibacterial Application

Bacterial infections have become a fatal threat because of the abuse of antibiotics in the world. Various gold (Au)-based nanostructures have been extensively explored as antibacterial agents to combat bacterial infections based on their remarkable chemical and physical characteristics. Many Au-based nanostructures have been designed and their antibacterial activities and mechanisms have been further examined and demonstrated. In this review, we collected and summarized current developments of antibacterial agents of Au-based nanostructures, including Au nanoparticles (AuNPs), Au nanoclusters (AuNCs), Au nanorods (AuNRs), Au nanobipyramids (AuNBPs), and Au nanostars (AuNSs) according to their shapes, sizes, and surface modifications. The rational designs and antibacterial mechanisms of these Au-based nanostructures are further discussed. With the developments of Au-based nanostructures as novel antibacterial agents, we also provide perspectives, challenges, and opportunities for future practical clinical applications.

Surfactant-Assisted Synthesis of Micro/Nano-Structured LiFePO4 Electrode Materials with Improved Electrochemical Performance

As an electrode material, LiFePO₄ has been extensively studied in the field of energy conversion and storage due to its inexpensive cost and excellent safety, as well as good cycling stability. However, it remains a challenge to obtain LiFePO₄ electrode materials with acceptable discharge capacity at low temperature. Here, micro/nano-structured LiFePO₄ electrode materials with grape-like morphology were fabricated via a facile solvothermal approach using ethanol and OA as the co-solvent, the surfactant as well as the carbon source. The structure and electrochemical properties of the LiFePO₄ material were investigated with x-ray diffraction (XRD), field emission scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the formation mechanism of the self-assembled micro/nano-structured LiFePO₄ was discussed as well. The micro/nano-structured LiFePO₄ electrode materials exhibited a high discharge capacity (142 mAh·g^-1) at a low temperature of 0 °C, and retained 102 mAh·g^-1 when the temperature was decreased to -20 °C. This investigation can provide a reference for the design of micro/nano-structured electrode materials with improvement of the electrochemical performance at low temperature.