An Iron-Based Fluorophosphate Cathode Material for K-Ion Batteries.

Autor: Saha D; Advanced Batteries and Ceramics Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, 400076, India., Desai P; Advanced Batteries and Ceramics Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, 400076, India., Sharma A; Advanced Batteries and Ceramics Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, 400076, India., Raghavendra Reddy V; UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore, India., Srihari V; High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Mumbai, India., Poswal HK; High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Mumbai, India., Das A; Advanced Batteries and Ceramics Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, 400076, India., Mukhopadhyay A; Advanced Batteries and Ceramics Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Jazyk: angličtina
Zdroj: ChemSusChem [ChemSusChem] 2024 Nov 09, pp. e202401935. Date of Electronic Publication: 2024 Nov 09.
DOI: 10.1002/cssc.202401935
Abstrakt: The development of a tavorite structured K- transition metal (T M )- fluorophosphate, having earth-abundant Fe as the only T M , crystallizing in the orthorhombic crystal system and facilitating stable-cum-reversible electrochemical K-extraction/insertion, has been reported here. Synthesized using low-cost precursors, KFePO 4 F has also been found to be air-stable. Detailed information pertaining to the bonding/structure, including lattice site occupancy, have been obtained via diffraction, Raman spectroscopy and FTIR, with XPS, Mössbauer and ESR revealing the oxidation states and nature of Fe in the as-synthesized condition and upon being subjected to electrochemical potassiation/depotassiation. The electrochemical K-insertion/extraction, supported by reversible Fe-redox, leads to a reversible K-storage capacity of ~102 mAh/g (within 1.5-4.0 V), along with a 1 st cycle Coulombic efficiency (CE) of ~93 % (with CE>99.9 % from 2 nd cycle onwards). Ex-situ X-ray diffraction, as well as operando synchrotron diffraction during galvanostatic cycling, indicates reversible changes in peak positions upon electrochemical K-extraction/insertion, with no evidence for structural change. When used as cathode material in K-ion 'full' cell (with hard carbon-based anode), a discharge capacity of ~68 mAh/g, along with capacity retention of ~70 % after 50 cycles, has been obtained; which confirms that this newly-developed earth-abundant Fe-based potassium fluorophosphate can be utilized for potential application in sustainable battery chemistries, like K-ion batteries.
(© 2024 Wiley-VCH GmbH.)
Databáze: MEDLINE
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