Li(Ni 0.8 , Co 0.1 , Mn 0.1 )O 2 (NCM-811) cathode materials have been commercialized recently, aiming to increase the specific capacity and specific energy of the lithium-ion battery for practical applications in electric vehicles. The surface coating has been proved to be an effective approach for the stabilization of NCM-based cathodes, which could reduce the structural instability and prevent surface reactions between the cathode materials and electrolytes. Herein, we demonstrate the facile synthesis of graphitic carbon nitride (g-C 3 N 4 )-coated NCM cathodes with both the sonication-assisted liquid exfoliation method (g-C 3 N 4 NS@NCM-811) and chemical vapor-assisted coating method (g-C 3 N 4 @NCM-811). It is discovered that coating with a thin g-C 3 N 4 layer could reduce the impedance of the NCM-811 cathode material, as well as increase the cycle stability of the cathode material, leading to increased capacity retention from 130 mA h/g (for the pristine sample) to 140 mA h/g after 225 cycles. While the coating of thick g-C 3 N 4 nanosheets could hinder the lithium intercalation, resulting in significant loss of specific capacity. This study paves the way toward practical applications of the g-C 3 N 4 -coated NCM-811 cathode materials.

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The properties exhibited by Ni-rich cathode materials were enhanced through the mixed coating layers of Li 3 PO 4 and boric acid. The scanning electron microscopy (SEM), the transmission electron microscope (TEM), the differential scanning calorimetry (DSC), the Electrochemical Impedance Spectroscopy (EIS), as well as the half-cell and full-cell charge-discharge tests were adopted for characterizing the structure and electrochemical properties exhibited by the cathode materials. As revealed by results, the Li 3 PO 4 and boric mixed coating layers can effectively reduce the surface area and protect the direct contact between cathode material particle surface and electrolyte, meanwhile improving the structural stability and cycle performance. The coating of fast ionic conductor contributes to enhance the specific capacity possessed by the Ni-rich cathode materials accordingly.

The transfer curve of the giant-magnetoresistive (GMR) magnetic head represents its most important property in applications, and it is calculated by the micromagnetic modeling of the free layer and the pinned layer in the heart of the GMR head. Affections of the bias hard magnetic layer and the anti-ferromagnetic pinning layer are modeled by effective magnetic fields. The simulated transfer curve agrees with experiment quite well, therefore the values of these effective magnetic fields can be determined by the model. A synthetic antiferromagnetic spin valve structure GMR head is also analyzed for comparison.