Issue 46, 2018

Electronic density distribution of Mn–N bonds by a tuning effect through partial replacement of Mn by Co or Ni in a sodium-rich hexacyanoferrate and its influence on the stability as a cathode for Na-ion batteries

Abstract

This study evaluates the effect of equimolar substitution of manganese by cobalt or nickel in hexacyanoferrate (HCF) open frameworks as electrode materials for Na-ion batteries. As the stability of Mn–N bonds is crucial to obtain long term stability and cyclability of manganese (Mn–HCF), the samples were analyzed thoroughly using several spectroscopic and structural methods. The XPS and infrared experiments reveal that the charge density around Fe is modulated by the presence of Co or Ni, which is associated with their high polarizing power, leading to decreased cell distortion as revealed by XRD. The Rietveld refinement demonstrated that the octahedra built by 3d metals and the cyanide nitrogen were distorted with the axial bond distances being larger than the equatorial distances. This octahedral distortion promotes the spin behavior of 3/2 for Mn2+ confirmed by magnetic experiments; the arising of this spin state is attributed to d orbital splitting determined by UV-Vis experiments. Therefore, the changes upon Mn substitution are related to the modification of the covalent character of Mn–N bonds, modulated by the effect of the Ni and Co polarizing power. All these properties improve the electrochemical stability of the Ni or Co substituted materials as Na-ion batteries, leading to higher capacity retention even at higher C-rates (5C) and good capacity recovery, in comparison with those obtained for Mn–HCF.

Graphical abstract: Electronic density distribution of Mn–N bonds by a tuning effect through partial replacement of Mn by Co or Ni in a sodium-rich hexacyanoferrate and its influence on the stability as a cathode for Na-ion batteries

Supplementary files

Article information

Article type
Paper
Submitted
05 ሴፕቴ 2018
Accepted
24 ኦክቶ 2018
First published
25 ኦክቶ 2018

Dalton Trans., 2018,47, 16492-16501

Electronic density distribution of Mn–N bonds by a tuning effect through partial replacement of Mn by Co or Ni in a sodium-rich hexacyanoferrate and its influence on the stability as a cathode for Na-ion batteries

M. Oliver-Tolentino, M. González M., H. Osiry, G. Ramos-Sánchez and I. González, Dalton Trans., 2018, 47, 16492 DOI: 10.1039/C8DT03595D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements