Na2FeP2O7 as a Promising Iron‐Based Pyrophosphate Cathode for Sodium Rechargeable Batteries: A Combined Experimental and Theoretical Study. (8th October 2012)

• Record Type: Journal Article
• Authors: Kim, Heejin; Shakoor, R. A.; Park, Chansun; Lim, Soo Yeon; Kim, Joo‐Seong; Jo, Yong Nam; Cho, Woosuk; Miyasaka, Keiichi; Kahraman, Ramazan; Jung, Yousung; Choi, Jang Wook
• Is Part Of: Advanced functional materials. Volume 23:Number 9(2013)
• Page Start: 1147
• Page End: 1155
• Publication Date: 2012-10-08
• Subjects: Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201201589
• Languages: English
• ISSNs: 1616-301X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Considering the promising electrochemical performance of the recently reported pyrophosphate family in lithium ion batteries as well as the increasing importance of sodium ion batteries (SIBs) for emerging large‐scale applications, here, the crystal structure, electrochemical properties, and thermal stability of Na₂FeP₂O₇, the first example ever reported in the pyrophosphate family for SIBs, are investigated. Na₂FeP₂O₇ maintains well‐defined channel structures (triclinic framework under the <italic>P1</italic> space group) and exhibits a reversible capacity of ≈90 mAh g⁻¹ with good cycling performance. Both quasi‐equilibrium measurements and first‐principles calculations consistently indicate that Na₂FeP₂O₇ undergoes two kinds of reactions over the entire voltage range of 2.0–4.5 V (vs Na/Na⁺): a single‐phase reaction around 2.5 V and a series of two‐phase reactions in the voltage range of 3.0–3.25 V. Na₂FeP₂O₇ shows excellent thermal stability up to 500 °C, even in the partially desodiated state (NaFeP₂O₇), which suggests its safe character, a property that is very critical for large‐scale battery applications.</p> </abstract>