Experimental and simulative insight into graphite-coated Ti substrate with high physicochemical stability

Abstract

The Ti substrate, with physicochemical stability and excellent electrical conductivity, is potential to fabricate all-solid-state batteries. However, the Titanium atoms at high-temperature synthesis makes it easy to react with active materials. Modifying the titanium surface with an inert protective layer while ensuring high electrical conductivity remains a significant challenge. Herein, a pencil was used to draw on the Ti substrate and subsequently sintering at a high temperature to obtain a graphite-coated Ti substrate (Ti-Graphite). The experimental results show that Ti-Graphite has a smoother surface and fewer defects in the graphite layer. Moreover, titanium carbide is formed at the interface of graphite and Ti substrate, which will enhance the physicochemical stability of the Ti-Graphite. To gain deep understanding of the evolution mechanism in the synthesis, molecular dynamics simulations were carried out to investigate it. The results exhibit that the voids at the C/Ti interface and stress in the model were significantly decreased after sintering and cooling treatment, proving that Ti-Graphite has a smoother surface, a more stable interface, and fewer defects at the atomic scale. Therefore, we provide a simple and facile strategy to obtain a Ti-graphite substrate with superior physicochemical stability, which reaveals excellent potential to synthesize high-performance all-solid-state batteries.

Keywords

• Graphite-coating
• Titanium substrate
• Molecular dynamics simulations
• Sintering mechanism