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Sodium Borates: Expanding the Electrolyte Selection for Sodiumā€Ion Batteries

Published version
Peer-reviewed

Change log

Authors

Ould, Darren MC 
Riesgoā€Gonzalez, Victor  ORCID logo  https://orcid.org/0000-0002-2433-8562
JĆ³nsson, Erlendur  ORCID logo  https://orcid.org/0000-0002-7776-0484

Abstract

jats:titleAbstract</jats:title>jats:pSodiumā€ion batteries (SIBs) are a promising gridā€level storage technology due to the abundance and low cost of sodium. The development of new electrolytes for SIBs is imperative since it impacts battery life and capacity. Currently, sodium hexafluorophosphate (NaPFjats:sub6</jats:sub>) is used as the benchmark salt, but is highly hygroscopic and generates toxic HF. This work describes the synthesis of a series of sodium borate salts, with electrochemical studies revealing that Na[B(hfip)jats:sub4</jats:sub>]ā‹…DME (hfip=hexafluoroisopropyloxy, Ojats:supi</jats:sup>Prjats:supF</jats:sup>) and Na[B(pp)jats:sub2</jats:sub>] (pp=perfluorinated pinacolato, Ojats:sub2</jats:sub>Cjats:sub2</jats:sub>(CFjats:sub3</jats:sub>)jats:sub4</jats:sub>) have excellent electrochemical performance. The [B(pp)jats:sub2</jats:sub>]jats:supāˆ’</jats:sup> anion also exhibits a high tolerance to air and water. Both electrolytes give more stable electrodeā€electrolyte interfaces than conventionally used NaPFjats:sub6</jats:sub>, as demonstrated by impedance spectroscopy and cyclic voltammetry. Furthermore, they give greater cycling stability and comparable capacity to NaPFjats:sub6</jats:sub> for SIBs, as shown in commercial pouch cells.</jats:p>

Description

Keywords

40 Engineering, 4016 Materials Engineering, 34 Chemical Sciences, 3406 Physical Chemistry, Cardiovascular, 7 Affordable and Clean Energy

Journal Title

Angewandte Chemie

Conference Name

Journal ISSN

0044-8249
1521-3757

Volume Title

Publisher

Wiley
Sponsorship
European Commission Horizon 2020 (H2020) ERC (835073)