Tailoring Thermal Expansion of (LiFe) 0.5 x Cu 2– x P 2 O 7 via Codoping LiFe Diatoms in Cu 2 P 2 O 7 Oxide

作者：Yumeng Xiang, Xiangkai Hao, Xiansheng Liu, Mengyue Wang, Jianjun Tian, Chaoyang Kang, Erjun Liang, Weifeng Zhang, Yu Jia · 发表于：Inorganic Chemistry · 年份：2022 · DOI：10.1021/acs.inorgchem.1c03219 · 被引用次数：11 · 研究领域：Thermal Expansion and Ionic Conductivity、Advanced Battery Materials and Technologies、Microwave Dielectric Ceramics Synthesis

Tailoring the thermal expansion coefficient of negative thermal expansion (NTE) materials to achieve near-zero thermal expansion has attracted great attention recently. Here, LiFe diatoms are adopted to substitute Cu in Cu 2 P 2 O 7 oxide to design Li–O–P and Fe–O–P linkages, with the stronger bond strength of Li–O and Fe–O compared to Cu–O and hence lowering the bond strength of P–O. With increasing the diatomic LiFe in (LiFe) 0.5 x Cu 2– x P 2 O 7, new Raman bands corresponding to LiFeP 2 O 7 appear and the NTE coefficient decreases gradually to near-zero thermal expansion at x = 1 (α v = −0.90 × 10 –6 °C –1, −100 to 55 °C). Comparing (LiFe) 0.5 CuP 2 O 7 with Cu 2 P 2 O 7 and LiFeP 2 O 7, the average bond length of P–O increases while the bond angle of P–O–P decreases, and this is verified by some weakened vibrational energies of terminal PO 3 and P–O–P, resulting in the obvious red shift of Raman bands. Ceramic (LiFe) 0.5 CuP 2 O 7 presents a lower difference in grain size and a higher relative density than Cu 2 P 2 O 7 and LiFeP 2 O 7 .