Na4‐αM2+α/2(P2O7)2 (2/3 ≤ α ≤ 7/8, M = Fe, Fe0.5Mn0.5, Mn): A Promising Sodium Ion Cathode for Na‐ion Batteries. Issue 6 (18th February 2013)

• Record Type: Journal Article
• Authors: Ha, Kwang‐Ho; Woo, Seung Hee; Mok, Duckgyun; Choi, Nam‐Soon; Park, Yuwon; Oh, Seung M.; Kim, Youngshol; Kim, Jeongsoo; Lee, Junesoo; Nazar, Linda F.; Lee, Kyu Tae
• Is Part Of: Advanced energy materials. Volume 3:Issue 6(2013:Jun.)
• Page Start: 770
• Page End: 776
• Publication Date: 2013-02-18
• Subjects: Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201200825
• Languages: English
• ISSNs: 1614-6832

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A new polyanion‐based compound, Na_3.12M_2.44(P₂O₇)₂ (M = Fe, Fe_0.5Mn_0.5, Mn) is synthesized and examined as a cathode for Na ion batteries. Off‐stoichiometric synthesis induces the formation of a Na‐rich phase, Na_3.32Fe_2.34(P₂O₇)₂ ‐ a member of the solid solution series Na_4‐αFe_2+α/2(P₂O₇)₂ (2/3 ≤ α ≤ 7/8) ‐ which delivers a reversible capacity of about 85 mA h g⁻¹ at ca. 3 V vs. Na/Na⁺ and exhibits very stable cycle performance. Above all, it shows fast kinetics for Na ions, delivering an almost constant 72% reversible capacity at rates between C/10 and 10C without the necessity for nanosizing or carbon coating. We attribute this to the spacious channel size along the <italic>a</italic>‐axis, along with a single phase transformation upon de/sodiation.</p> </abstract>