Na2.4Al0.4Mn2.6O7 anionic redox cathode material for sodium ion batteries - a combined experimental and theoretical approach to elucidate its charge storage mechanism

DOI: 10.1039/D1TA05137G

Authors: Cindy Soares (Lancaster University) , Begoña Silvan (Lancaster University; The Faraday Institution) , Yong-Seok Choi (University College London; The Faraday Institution) , Veronica Celorrio (Diamond Light Source) , Giannantonio Cibin (Diamond Light Source) , David O. Scanlon (University College London; The Faraday Institution; Diamond Light Source) , Nuria Tapia-Ruiz (Lancaster University; The Faraday Institution)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Materials Chemistry A

State: Published (Approved)
Published: December 2021
Diamond Proposal Number(s): 21847

Abstract: Here we report the synthesis via ceramic methods of the high-performance Mn-rich Na2.4Al0.4Mn2.6O7 oxygen-redox cathode material for Na-ion batteries which we use as a testbed material to study the effects of Al substitution and subsequent Na excess in the high-capacity, anionic redox-based cathode material Na2Mn3O7. The material shows a stable electrochemical performance, with a specific capacity of 200 mAh g-1 in the 1.5 - 4.7 voltage window at C/20 and capacity retention of 90 % after 40 cycles. Using a combination of electrochemical and structural analysis together with hybrid density functional theory calculations we explain the behaviour of this material with changes in Mn/anionic redox reactions and associated O2 release reactions occurring in the material during electrochemical cycling (Na insertion/extraction) and compare these findings to Na2Mn3O7. We expect that these results will advance understanding of the effect of dopants in Mn-rich cathode materials with oxygen redox activity to pave their way towards real applications in high-performing sodium-ion battery applications.

Diamond Keywords: Batteries; Sodium-ion

Subject Areas: Materials, Chemistry, Energy


Instruments: B18-Core EXAFS

Added On: 06/01/2022 09:12

Documents:
d1ta05137g.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Energy Materials Chemistry Materials Science

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Absorption Near Edge Structure (XANES)