Cu2S has wide-ranging applications in the energy field, particularly as electrode materials and components of energy storage devices. However, the migration of copper ions is prone to component segregation and copper precipitation, impairing long-term thermal stability and service performance. Ce2S3 not only possesses the unique 4f electron layer structure of Ce but also has high thermal stability and chemical inertness. Here, we report for the first time that the thermal stability and mechanical properties of Cu2S can be significantly enhanced by introducing the dispersed phase Ce2S3. Thermogravimetry—differential scanning calorimetry (TG-DSC) results show that the addition of 6 wt% Ce2S3 improves the thermal stability of Cu2S sintered at 400 °C. X-ray diffraction (XRD) results indicate that the crystal structure of Cu2S gradually transforms to tetragonal Cu1.96S and orthorhombic Cu1.8S phase at 400 °C with the increase of Ce2S3 addition. Scanning electron microscopy (SEM) results show that the particle size gradually decreased with the increase of Ce2S3 amount, indicating that the Ce2S3 addition increased the reactivity. The Ce content in Cu2S increased gradually with the increase of Ce2S3 amount at 400–600 °C. The 7 wt% Ce2S3-Cu2S exhibits paramagnetic behavior with a saturation magnetization of 1.2 µB/Ce. UV-Vis analysis indicates that the addition of Ce2S3 can reduce the optical energy gap and enrich the band structure of Cu2S. With increasing addition of Ce2S3 and rising sintering temperature, the density of Ce2S3-Cu2S gradually increases, and the hardness of Ce2S3-Cu2S increases by 52.5% at 400 °C and by 34.2% at 600 °C. The friction test results show that an appropriate addition amount of Ce2S3 can increase the friction coefficients of Cu2S. Ce2S3 modification offers a novel strategy to simultaneously enhance the structural and service stability of Cu2S by regulating Cu ion diffusion and suppressing compositional fluctuations.
Sun et al. (Wed,) studied this question.