Na4Fe3(PO4)2P2O7 的阴离子基团掺杂稳定其结构并改善钠离子存储的电化学性能,ACS Sustainable Chemistry & Engineering

当前位置： X-MOL 学术 › ACS Sustain. Chem. Eng. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Na4Fe3(PO4)2P2O7 的阴离子基团掺杂稳定其结构并改善钠离子存储的电化学性能
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2023-12-08 , DOI: 10.1021/acssuschemeng.3c06667
Mingzu Liu ₁ , Min Li ₁ , Bolun Zhang ₁ , Houmou Li ₁ , Jiaxin Liang ₁ , Xinyu Hu ₁ , Haimei Liu ₁ , Zi-Feng Ma ₂

Affiliation

由于其低成本和高稳定性，铁基混合聚阴离子化合物Na ₄ Fe ₃ (PO ₄ ) ₂ P ₂ O ₇被广泛研究用作钠离子电池正极材料。然而，其发展受到低电导率和有限扩散动力学的限制。在这项工作中，我们选择用SiO ₄^4–基团取代PO ₄^3–基团，以增强电子电导率和扩散动力学，同时这种结构替代保持了材料的完整性。此外，非活性位点的这种取代提高了电化学性能而不降低理论容量。此外，它在重复充电和放电过程中稳定了晶体结构。结果，这种SiO ₄^4-掺杂的Na ₄ Fe ₃ (PO ₄ ) ₂ P ₂ O ₇表现出改善的电化学性能。例如，经过5000次循环后，其在0.1 C倍率下的容量为119.4 mA hg ^{–1 ，在50 C倍率下的容量为60.7 mA hg}^–1，并保留了84.2%的容量。此外，理论计算揭示了基质材料结构中SiO ₄^4–的掺杂形式和占有率。相信这项工作为阴离子基团的掺杂改性以提高钠离子存储正极材料的电化学性能提供了新的视角。

"点击查看英文标题和摘要"

Anionic Group Doping of Na4Fe3(PO4)2P2O7 Stabilizes Its Structure and Improves Electrochemical Performance for Sodium Ion Storage

Due to its low cost and high stability, the iron-based mixed polyanionic compound Na₄Fe₃(PO₄)₂P₂O₇ is widely studied for use as a sodium-ion battery cathode material. However, its development is limited by a low electrical conductivity and restricted diffusion kinetics. In this work, we chose to replace the PO₄^3– group with the SiO₄^4– group to enhance the electronic conductivity and diffusion kinetics, while this structural substitution maintains the integrity of the material. Furthermore, this substitution at a nonactive site improves the electrochemical performance without reducing the theoretical capacity. Additionally, it stabilizes the crystal structure during the repeated charging and discharging process. As a result, this SiO₄^4– doped Na₄Fe₃(PO₄)₂P₂O₇ exhibits improved electrochemical properties. For instance, it achieves a capacity of 119.4 mA h g^–1 at a rate of 0.1 C and 60.7 mA h g^–1 at 50 C after 5000 cycles with 84.2% of its capacity retained. Moreover, theoretical calculations revealed the doping form and occupancy of SiO₄^4– in the host material structure. It is believed that this work provides a new perspective on doping modification with anionic groups to improve the electrochemical performance of cathode materials for sodium ion storage.

更新日期：2023-12-08

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南