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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Titanium- and niobium-doped fluorophosphates as positive electrodes for sodium-ion batteries

Full text
Author(s):
Morais, William G. [1] ; Leite, Marina M. [1] ; Torresi, Roberto M. [1]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Dept Quim Fundamental, Inst Quim, Av Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: JOURNAL OF ELECTROANALYTICAL CHEMISTRY; v. 897, SEP 15 2021.
Web of Science Citations: 0
Abstract

Sodium fluorophosphates are among the most promising materials for positive electrodes in sodium-ion batteries; however, their low electronic conductivity, kinetics limitations, and structural instability prevent them from reaching their full potential. We obtained sodium vanadium fluorophosphates (NVPF) doped with Ti4+ (NVTPF) and Nb5+ (NVNPF) via an original low-temperature synthesis. It was observed that Ti4+ doping facilitated access to electrode sites and provided higher capacities at high current densities while Nb5+ provided a 91.7% capacity retention from the 20th to 200th cycle, which was over the 80.1% capacity retention of NVPF. Moreover, both NVTPF and NVNPF provided diffusion coefficients in the range of similar to 10(-10) cm(2) s(-1), which was better than similar to 10(-12) cm(2) s(-1) of NVPF. Additionally, electrochemical impedance spectroscopy and ex situ X-ray diffraction measurements confirmed that Ti4+ enhanced the electrode kinetics and stabilized its structure through sodiation/desodiation reactions. The results presented in this paper might provide insights and new directions to enhance the electrochemical storage properties of fluorophosphates. (AU)

FAPESP's process: 15/26308-7 - Optimization of the physicochemical properties of nano -structured materials for applications in molecular recognition, catalysis and energy conversion/storage
Grantee:Roberto Manuel Torresi
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 20/07768-5 - Materials for positive high voltage electrodes in Li + and Na + batteries
Grantee:Marina Moraes Leite
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 18/23072-0 - Study of new active materials for application as positive and negative electrodes in sodium ion batterries
Grantee:William Gomes de Morais
Support Opportunities: Scholarships in Brazil - Post-Doctoral