Dense TiB2 Coating with Fully Bonded Lamellae Deposited by Low-Pressure Plasma Spraying and Its Exploratory Application as the Negative Electrode of a Lithium-Ion Battery

Depositing dense or bulk-like superhigh-temperature boride ceramic coatings by thermal spraying is a challenging but attractive method for applications in the electronics industry due to the excellent electrical and thermal conductivity of the resulting coatings. Herein, a dense TiB₂ coating deposited by plasma spraying was investigated by modifying the characteristics of the plasma jet in a controlled environment chamber. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to analyze the phase and microstructure of the sprayed coating. The coating was then used as the negative electrode for a lithium-ion battery. The results showed that a dense TiB₂ coating with fully bonded lamellae was obtained with an Ar/He plasma jet under a very low pressure, resulting in a porosity of 3.05%. A coarse coating with many unmelted particles was deposited with an Ar/H₂ plasma jet under a low pressure. The dense coating with a low electrical resistivity (1.17 × 10⁻³ Ω cm) presented charge/discharge performance, but its specific capacity of 17.22 mAh g⁻¹ requires improvement.