Han Qinghao, Hu Ya'nan, Gao Shuting, Yang Zonghua, Liu Xingjun, Wang Cuiping, Han Jiajia
College of Materials and Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials, Xiamen University, Xiamen, 361005, P. R. China.
Xiamen Key Laboratory of High Performance Metals and Materials, Xiamen University, Xiamen, 361005, P. R. China.
ChemSusChem. 2023 Oct 20;16(20):e202300823. doi: 10.1002/cssc.202300823. Epub 2023 Aug 25.
Prussian blue analogues (PBAs) are promising cathode materials for sodium-ion batteries (SIBs) due to their tunable chemistry, open channel structure, and low cost. However, excessive crystal water and volume expansion can negatively impact the lifetime of actual SIBs. In this study, a novel iron nitroprusside: Fe[Fe(CN) NO] (PBN) was synthesized to effectively eliminate the detrimental effects of crystal water on the reversible capacity and cycling stability of PBA materials. Experiments and DFT calculations demonstrated that PBN has lower crystal water and volume expansion compared to Fe[Fe(CN) ] (PB). Also, the N=O bond in PBN significantly reduces the diffusion potential of Na in the skeleton. Without any modification, the cathode material exhibited a capacity of up to 148.6 mAh g at 50 mA g as well as maintained 102.9 mAh g after 200 cycles. This work expands our knowledge of the crystal structure of PBA cathode materials and facilitates the rational design of high-quality PBA cathodes for SIBs.
普鲁士蓝类似物（PBAs）因其可调节的化学性质、开放的通道结构和低成本，是钠离子电池（SIBs）很有前景的阴极材料。然而，过多的结晶水和体积膨胀会对实际SIBs的寿命产生负面影响。在本研究中，合成了一种新型硝普铁：Fe[Fe(CN)NO]（PBN），以有效消除结晶水对PBA材料可逆容量和循环稳定性的不利影响。实验和密度泛函理论（DFT）计算表明，与Fe[Fe(CN)]（PB）相比，PBN具有更低的结晶水和体积膨胀。此外，PBN中的N=O键显著降低了Na在骨架中的扩散势垒。未经任何改性，该阴极材料在50 mA g下的容量高达148.6 mAh g，并且在200次循环后仍保持102.9 mAh g。这项工作扩展了我们对PBA阴极材料晶体结构的认识，并有助于合理设计用于SIBs的高质量PBA阴极。
