Entropy profile of NCR 18650 cylindrical cell at various states of health.

Entropy measurement at various states of charge (SOC) is a potential non-destructive tool for characterizing lithium-ion batteries; however, traditional potentiometric methods are time-consuming. To address this, we developed a fast potentiometric method that estimates entropy by employing charging after pulse discharging to partly eliminate voltage relaxation. This method, combined with precise mathematical processing, reduces estimation time by approximately 4.

Revealing Phase Transition in Ni-Rich Cathodes via a Nondestructive Entropymetry Method.

With the expanding requirements of recent energy regulations and economic interest in high-performance batteries, the need to improve battery energy density and safety has gained prominence. High-energy-density lithium batteries, employed in next-generation energy storage devices, rely on nickel-rich cathode materials. Since they have extremely high charge/discharge capacity, high operating voltage, prolonged cycle life, and lower cost, nickel-rich cathode materials such as Ni-rich NCM (LiNiCoMnO) and Ni-rich NCA (LiNiCoAlO) are of particular interest to researchers.

Structural and Chemical Modifications Towards High-Performance of Triboelectric Nanogenerators.

Harvesting abundant mechanical energy has been considered one of the promising technologies for developing autonomous self-powered active sensors, power units, and Internet-of-Things devices. Among various energy harvesting technologies, the triboelectric harvesters based on contact electrification have recently attracted much attention because of their advantages such as high performance, light weight, and simple design. Since the first triboelectric energy-harvesting device was reported, the continuous investigations for improving the output power have been carried out.

3D Hierarchical Nanocrystalline CuS Cathode for Lithium Batteries.

Conductive and flexible CuS films with unique hierarchical nanocrystalline branches directly grown on three-dimensional (3D) porous Cu foam were fabricated using an easy and facile solution processing method without a binder and conductive agent for the first time. The synthesis procedure is quick and does not require complex routes. The structure and morphology of the as-deposited CuS/Cu films were characterized by X-ray diffraction and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and transmission electron spectroscopy, respectively.

A Review of Piezoelectric PVDF Film by Electrospinning and Its Applications.

With the increase of interest in the application of piezoelectric polyvinylidene fluoride (PVDF) in nanogenerators (NGs), sensors, and microdevices, the most efficient and suitable methods of their synthesis are being pursued. Electrospinning is an effective method to prepare higher content β-phase PVDF nanofiber films without additional high voltage poling or mechanical stretching, and thus, it is considered an economically viable and relatively simple method. This work discusses the parameters affecting the preparation of the desired phase of the PVDF film with a higher electrical output.

Fabrication and Properties of Carbon-Encapsulated Cobalt Nanoparticles over NaCl by CVD.

Carbon-encapsulated cobalt (Co@C) nanoparticles, with a tunable structure, were synthesized by chemical vapor deposition using Co nanoparticles as the catalyst and supported on a water-soluble substrate (sodium chloride), which was easily removed by washing and centrifugation. The influences of growth temperature and time on the structure and magnetic properties of the Co@C nanoparticles were systematically investigated. For different growth temperatures, the magnetic Co nanoparticles were encapsulated by different types of carbon layers, including amorphous carbon layers, graphitic layers, and carbon nanofibers.