材料科学
氟化物
插层(化学)
阴极
扩散
离子
储能
八面体
化学工程
纳米技术
分析化学(期刊)
无机化学
物理化学
热力学
功率(物理)
化学
物理
色谱法
量子力学
工程类
作者
Jungmin Kang,Jinho Ahn,Hyun Young Park,Wonseok Ko,Yongseok Lee,Seokjin Lee,Sangyeop Lee,Sung-Kyun Jung,Jongsoon Kim
标识
DOI:10.1002/adfm.202201816
摘要
Grid-scale energy storage system is the need of batteries with low-cost, high-energy-density, and long cycle life. The requirement promotes the discovery of cathode materials enabling the storage of charge carrier ion within the open framework crystal structure having multi-dimensional diffusion path exhibiting small volume change. Herein, Na2TiFeF7 is reported as a promising fluoride-based cathode material for sodium-ion batteries (SIBs). Through combined studies using various experiments and first-principles calculations, it is confirmed that Na2TiFeF7 with 3D diffusion pathway delivers a specific capacity of ≈185 mAh g−1 at C/20 with an average operation voltage of ≈3.37 V (vs Na+/Na) including the high Fe2+/3+ redox potential (≈3.75 V). Even at 5C, a specific capacity of ≈136 mAh g−1 is retained (≈73% of its theoretical capacity) owing to the low band gap energy (≈1.83 eV) and the low activation barrier energies (≈477.68 meV) required for facile Na+ diffusion, indicating the excellent power-capability. Moreover, Na2TiFeF7 composed of three-dimensionally interconnected (Fe, Ti)F6 octahedra delivers an outstanding capacity retention of ≈71% after 600 cycles at 1 C owing to the small structural volume change (≈0.96%) during Na+ de/intercalation. These findings provide insight into the development of fluoride-based novel cathode materials for high-performance SIBs.
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