中南大学纪效波团队报道了全天候全钠离子电池用Na₄Fe₃(PO₄)₂(P₂O₇)的铝离子化学。相关研究成果发表在2024年1月23日出版的《科学通报》。

Na₄Fe₃(PO₄)₂(P₂O₇) (NFPP)作为钠离子电池（SIBs）阴极，由于其具有成本效益和NASICON型结构特征，目前正引起越来越多的关注。然而，由于电子和Na⁺电导率缓慢，其实际应用受到严重的容量衰减和较差的倍率能力的阻碍。

该文通过调节结构/界面耦合电子/离子输运，精心设计了具有宽操作温度的多价阳离子取代微孔Na_3.9Fe_2.9Al_0.1(PO₄)₂(P₂O₇) (NFAPP)。三价Al³⁺取代引起的Na空位和电荷重排大大降低了离子的扩散势垒，从而赋予了更快的电子传输和Na⁺迁移率。更重要的是，现有的Al–O–P键增强了局部环境，减轻了（脱）钠过程中的体积振动，实现了高度可逆的价态变化和结构演变。

因此，在半电池/全电池中，证明了显著的可循环性（超过10000个循环）、超快速率能力（200℃）和卓越的全气候稳定性（-40–60°C）。有鉴于此，合理的工作可能会为提高NFPP的电化学性能提供一种可行的策略，从而揭示钠铁混合磷酸盐材料的巨大应用前景。

附：英文原文

Title: Aluminum ion chemistry of Na4Fe3(PO4)2(P2O7) for all-climate full Na-ion battery

Author: Jinqiang Gao, Jingyao Zeng, Weishun Jian, Yu Mei, Lianshan Ni, Haoji Wang, Kai Wang, Xinyu Hu, Wentao Deng, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji

Issue&Volume: 2024/01/23

Abstract: Na4Fe3(PO4)2(P2O7) (NFPP) is currently drawing increased attention as a sodium-ion batteries (SIBs) cathode due to the cost-effective and NASICON-type structure features. Owing to the sluggish electron and Na+ conductivities, however, its real implementation is impeded by the grievous capacity decay and inferior rate capability. Herein, multivalent cation substituted microporous Na3.9Fe2.9Al0.1(PO4)2(P2O7) (NFAPP) with wide operation-temperature is elaborately designed through regulating structure/interface coupled electron/ion transport. Greatly, the derived Na vacancy and charge rearrangement induced by trivalent Al3+ substitution lower the ions diffusion barriers, thereby endowing faster electron transport and Na+ mobility. More importantly, the existing Al–O–P bonds strengthens the local environment and alleviates the volume vibration during (de)sodiation, enabling highly reversible valence variation and structural evolution. As a result, remarkable cyclability (over 10,000 loops), ultrafast rate capability (200 C), and exceptional all-climate stability (40–60 °C) in half/full cells are demonstrated. Given this, the rational work might provide an actionable strategy to promote the electrochemical property of NFPP, thus unveiling the great application prospect of sodium iron mixed phosphate materials.

DOI: 10.1016/j.scib.2024.01.026

Source: https://www.sciencedirect.com/science/article/abs/pii/S2095927324000537