A form-stable ternary nitrate (LiNO₃·3H₂O-KNO₃-NaNO₃) composite phase change material (CPCM) with modified expanded graphite (MEG) as carrier was investigated. In order to improve the hydrophilicity of expanded graphite (EG) and its compatibility with ternary nitrate, the SiO₂ particles prepared by sol-gel method was used as modifier to form a hydrophilic coating on EG to obtain MEG. The pore structure morphology as well as the adsorption capacity for ternary nitrate of EG and MEG were analyzed in detail. The shape-stability and thermal properties of the obtained CPCM were also evaluated. The results showed that the MEG with 15 wt% SiO₂ exhibited optimal affinity to water and ternary nitrate PCM. With the addition of 20 wt% MEG, the configured CPCM owned a suitable phase change temperature (21.66 °C), high phase change enthalpy (158.7 J/g), low supercooling degree (1.56 °C) and outstanding thermal conductivity (4.565 W/m·K). Moreover, the thermal performance differences of the CPCM were relatively small after 200 thermal cycles, indicating that the prepared CPCM can be applied in the room temperature thermal energy storage technology.

以改性膨胀石墨（MEG）为载体，研究了形状稳定的三元硝酸盐（LiNO ₃ ·3H ₂ O-KNO ₃ -NaNO ₃）复合相变材料（CPCM）。为了提高膨胀石墨（EG）的亲水性及其与硝酸三元酯的相容性，采用溶胶-凝胶法制备的SiO ₂颗粒作为改性剂，在EG上形成亲水涂层，得到MEG。详细分析了EG和MEG的孔结构形态以及对三元硝酸盐的吸附能力。还评估了所获得的CPCM的形状稳定性和热性能。结果表明，MEG含15 wt％的SiO ₂对水和三元硝酸盐PCM具有最佳亲和力。通过添加20 wt％的MEG，配置的CPCM具有合适的相变温度（21.66°C），高相变焓（158.7 J / g），低过冷度（1.56°C）和出色的导热性（4.565 W / m·K）。此外，在200个热循环后，CPCM的热性能差异相对较小，表明所制备的CPCM可以应用于室温热能存储技术。