Impact of carbonate-based electrolytes on the electrochemical activity of carbon-coated Na3V2(PO4)2F3 cathode in full-cell assembly with hard carbon anode

Krishnan Subramanyan; Yun-Sung Lee; Vanchiappan Aravindan

doi:10.1016/j.jcis.2020.08.043

Impact of carbonate-based electrolytes on the electrochemical activity of carbon-coated Na₃V₂(PO₄)₂F₃ cathode in full-cell assembly with hard carbon anode

J Colloid Interface Sci. 2021 Jan 15;582(Pt A):51-59. doi: 10.1016/j.jcis.2020.08.043. Epub 2020 Aug 11.

Authors

Krishnan Subramanyan¹, Yun-Sung Lee², Vanchiappan Aravindan³

Affiliations

¹ Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India.
² Department of Advanced Chemicals and Engineering, Chonnam National University, Gwang-ju 61186, Republic of Korea.
³ Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati 517507, India. Electronic address: aravind_van@yahoo.com.

PMID: 32805630
DOI: 10.1016/j.jcis.2020.08.043

Abstract

An immense effort has been put into developing high-performance electrodes to commercialize sodium-ion batteries, but research on developing an efficient electrolyte is lacking. This study aims to find the best carbonate-based electrolyte systems by incorporating the existing ideas reported in this field. The sodium superionic conductor (NASICON) type Na₃V₂(PO₄)₂F₃-C (NVPF-C) was chosen as a cathode, and its compatibility with four different carbonate-based electrolyte solutions was studied in the half-cell assembly. Additionally, full-cell assembly with hard carbon as an anode is also explored. Binary and ternary combinations of the solvents ethylene carbonate, propylene carbonate, and dimethyl carbonate were employed with and without fluoroethylene carbonate as an additive. A systematic study was performed, including the in-situ impedance technique, and to determine the compatibility. Detailed galvanostatic studies for NVPF-C based half-cells, as well as hard carbon/NVPF-C full-cells, are performed, which shows that 1 M NaClO₄ in propylene carbonate:dimethyl carbonate + fluoroethylene carbonate is a better electrolyte composition for this assembly. Subsequently, a temperature study was carried out on this electrolyte to test its performance.

Keywords: Electrolytes; Hard carbon; In-situ impedance; Na(3)V(2)(PO(4))(2)F(3); Sodium-ion batteries.