RIS ID
140719
Abstract
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Mn-based hexacyanoferrate NaxMnFe(CN)6 (NMHFC) has been attracting more attention as a promising cathode material for sodium ion storage owing to its low cost, environmental friendliness, and its high voltage plateau of 3.6 V, which comes from the Mn2+/Mn3+ redox couple. In particular, the Na-rich NMHFC (x > 1.40) with trigonal phase is considered an attractive candidate due to its large capacity of ≈130 mAh g−1, delivering high energy density. Its unstable cycle life, however, is holding back its practical application due to the dissolution of Mn2+ and the trigonal-cubic phase transition during the charge–discharge process. Here, a novel hexacyanoferrate (Na1.60Mn0.833Fe0.167[Fe(CN)6], NMFHFC-1) with Na-rich cubic structure and dual-metal active redox couples is developed for the first time. Through multiple structural modulation, the stress distortion is minimized by restraining Mn2+ dissolution and the trigonal-cubic phase transition, which are common issues in manganese-based hexacyanoferrate. Moreover, NMFHFC-1 simultaneously retains an abundance of Na ions in the framework. As a result, Na1.60Mn0.833Fe0.167[Fe(CN)6] electrode delivers high energy density (436 Wh kg−1) and excellent cycle life (80.2% capacity retention over 300 cycles), paving the way for the development of novel commercial cathode materials for sodium ion storage.
Publication Details
Li, W., Han, C., Wang, W., Xia, Q., Chou, S., Gu, Q., Johannessen, B., Liu, H. & Dou, S. (2019). Stress Distortion Restraint to Boost the Sodium Ion Storage Performance of a Novel Binary Hexacyanoferrate. Advanced Energy Materials,