香港理工大学徐正龍团队报道了通过将疏钠石墨转换为亲钠和高容量阳极实现高能钠离子电池。相关研究成果发表在2024年8月31日出版的《德国应用化学》。

由于地壳中钠元素丰富，钠离子电池（SIBs）被认为是锂离子电池在固定储能应用中的有前景的补充。共渗化学使用成本效益高的石墨作为阳极，而石墨的低容量（<130 mAh g^-1）和高氧化还原电位（>0.6 V vs.Na/Na⁺）显著限制了SIBs的能量密度。

该文中，研究人员通过共插层和沉积反应将高容量钠金属诱导成亲钠三元石墨插层化合物（t-GICs），从而实现高容量和低工作电压（0.18V）的Na/t-GIC阳极。新阳极在550次循环中表现出99.7%以上的高库仑效率，在6℃下（每次充电10分钟）的高倍率容量为588.4 mAh g^-1。

当它与Na₃V₂（PO₄）₂F₃（NVPF）阴极配对时，SIBs显示出259 Wh kg^-1的高能量密度，两个电极都超过了商用LiFePO₄//石墨电池。出色的阳极性能归因于石墨通过操纵醚溶剂，和t-GIC薄片之间的原位生成空间来稳定地容纳Na金属，从而定制了亲钠性。

研究人员在亲钠石墨材料上稳定镀钠/剥离的发现为开发先进的SIBs提供了一种有效的方法。

附：英文原文

Title: High-Energy Sodium Ion Batteries Enabled by Switching Sodiophobic Graphite into Sodiophilic and High-Capacity Anodes

Author: Linlong Lyu, Yichun Zheng, Yingkai Hua, Jien Li, Yuyang Yi, Yang Sun, Zheng-Long Xu

Issue&Volume: 2024-08-31

Abstract: Owing to the crustal abundance of sodium element, sodium ion batteries (SIBs) are considered a promising complementary to lithium-ion battery for stationary energy storage applications. The cointercalation chemistry enables the use of cost-effective graphite as anodes, whereas the low capacity (<130 mAh g-1) and high redox potential (>0.6 V vs. Na/Na+) of graphite significantly limit the energy density of SIBs. Herein, we induce the high-capacity Na metal into sodiophilic ternary graphite intercalation compounds (t-GICs) via co-intercalation and deposition reactions, thereby achieving Na/t-GIC anodes with high capacities and low working voltage (0.18 V). The new anodes exhibit high coulombic efficiencies of above 99.7 % over 550 cycles and a high-rate capacity of 588.4 mAh g-1 at 6 C (10 min per charge). When it is paired with Na3V2(PO4)2F3 (NVPF) cathodes, the SIBs demonstrate a high energy density of 259 Wh kg-1both electrodes surpassing that of commercial LiFePO4//graphite batteries. The outstanding anode performance is attributed to the tailored sodiophilicity of graphite through manipulating the ether solvents and the in-situ generated space among t-GIC flakes to stably accommodate Na metal. Our findings for stable Na plating/striping on sodiophilic graphite materials provide an effective approach for developing advanced SIBs.

DOI: 10.1002/anie.202410253

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202410253