Feng Yi-Hu, Liu Mengting, Qi Wenli, Liu Haoliang, Liu Qiang, Yang Chao, Tang Yongwei, Zhu Xu, Sun Shuai, Li Yuan-Meng, Chen Tian-Ling, Xiao Bing, Ji Xiao, You Ya, Wang Peng-Fei
Center of Nanomaterials for Renewable Energy, State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, P. R. China.
School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China.
Angew Chem Int Ed Engl. 2025 Jan 15;64(3):e202415644. doi: 10.1002/anie.202415644. Epub 2024 Nov 6.
High-voltage sodium metal batteries (SMBs) present a viable pathway towards high-energy-density sodium-based batteries due to the competitive cost advantage and abundant supply of sodium resources. However, they still suffer from severe capacity decay induced by the notorious decomposition of the electrolyte under high voltage and unstable cathode/electrolyte interphase (CEI). In addition, the high reactivity of Na metal and flammable electrolytes push SMBs to their safety limits. Herein, a special dual-anion aggregated Na solvation structure is designed in a nonflammable trimethyl phosphate-based localized high-concentration electrolyte, and a gradient CEI enriched with phosphorus and boron compounds is formed on the cathode. This thin and stable interphase effectively suppresses the parasitic reaction, improves the interfacial stability of the cathode, and facilitates Na transport through the interface by the synergistic effect of multi-components, thus optimizing the cycling stability and safety of SMBs. The NaNiFeMnTiO//Na batteries employing such electrolyte provide a discharge capacity of 167.5 mAh g and high retention in the capacity of 85.2 % after 800 cycles at 1 C. This approach offers a general strategy for the design of flame-retardant high-voltage electrolytes and the practical application of SMBs.
高压钠金属电池（SMBs）由于具有成本竞争优势和钠资源供应丰富，为高能密度钠基电池提供了一条可行的途径。然而，它们仍然受到高电压下电解质臭名昭著的分解以及不稳定的阴极/电解质界面（CEI）所导致的严重容量衰减的困扰。此外，钠金属的高反应活性和易燃的电解质将SMBs推向了安全极限。在此，在一种不可燃的磷酸三甲酯基局部高浓度电解质中设计了一种特殊的双阴离子聚集钠溶剂化结构，并在阴极上形成了富含磷和硼化合物的梯度CEI。这种薄而稳定的界面有效地抑制了寄生反应，提高了阴极的界面稳定性，并通过多组分的协同作用促进了钠通过界面的传输，从而优化了SMBs的循环稳定性和安全性。采用这种电解质的NaNiFeMnTiO//Na电池在1 C下800次循环后提供了167.5 mAh g的放电容量和85.2 %的高容量保持率。这种方法为阻燃高压电解质的设计和SMBs的实际应用提供了一种通用策略。
