A binary ionogel electrolyte for the realization of an all solid-state electrical double-layer capacitor performing at low temperature

Emmanuel Pameté; Zhuanpei Wang; François Béguin

doi:10.1002/cssc.202400596

Scientific Information System of the Poznań University of Technology

PL EN

Main page / Publications / A binary ionogel electrolyte for the realization of an all solid-state electrical double-layer capacitor performing at low temperature

Submit a comment

Article

Download BibTeX

Title

A binary ionogel electrolyte for the realization of an all solid-state electrical double-layer capacitor performing at low temperature

Authors

Emmanuel Pameté (WTCH) ^{[ 1 ][ 7.6 ][ D ]}
Zhuanpei Wang (WTCH) ^{[ 1 ][ 7.6 ][ P ]}
François Béguin (WTCH) ^{[ 1 ][ 7.6 ][ P ]}

^{[ 1 ]} Instytut Chemii i Elektrochemii Technicznej, Wydział Technologii Chemicznej, Politechnika Poznańska | ^{[ D ]} phd student | ^{[ P ]} employee

Scientific discipline (Law 2.0)

[7.6] Chemical sciences

Year of publication

2024

Published in

Chemistry & Sustainability

Journal year: 2024 | Journal volume: early view | Journal number: early view

Article type

scientific article

Publication language

english

Keywords

EN

all solid-state capacitor
binary ionic liquid
binary ionogel membrane
hierarchical micro/mesoporous carbon
low-temperature operation
PVdF-HFP matrix

Abstract

EN Over the last years, solid-state electrolytes made of an ionic liquid (IL) confined in a solid (inorganic or polymer) matrix, also known as ionogels, have been proposed to solve the leakage problems occurring at high temperatures in classical electrical double-layer capacitors (EDLCs) with an organic electrolyte, and thereof improve the safety. However, making ionogel-based EDLCs perform with reasonable power at low temperature is still a major challenge due to the high melting point of the confined IL. To overcome these limitations, the present contribution discloses ionogel films prepared in a totally oxygen/moisture-free atmosphere by encapsulating 70 wt % of an equimolar mixture of 1 ethyl 3-methylimidazolium bis(fluorosulfonyl)imide and 1 ethyl 3-methylimidazolium tetrafluoroborate - [EMIm][BF4]0.5[FSI]0.5 - into a poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) network. The further called “binary ionogel” films demonstrated a high flexibility and a good ionic conductivity of 5.8 mS cm-1 at 20 °C. Contrary to the ionogels prepared from either [EMIm][FSI] or [EMIm][BF4], displaying melting at Tm = -16 °C and -7 °C, respectively, the crystallization of confined [EMIm][BF4]0.5[FSI]0.5 is quenched in the binary ionogel, which shows only a glass transition at -101 °C. This quenching enables an increased ionicity and ionic diffusion at the interface with the PVdF host network, leading the binary ionogel membrane to display higher ionic conductivity below -20 °C than the parent binary [EMIm][BF4]0.5[FSI]0.5 liquid. Laminate EDLCs were built with a 100 µm thick binary ionogel separator and electrodes made from a hierarchical micro-/mesoporous MgO-templated carbon containing a reasonable proportion of mesopores to enhance the mass transport of ions, especially at low temperature where the ionic diffusion noticeably decreases. The EDLCs operated up to 3.0 V with ideal EDL characteristics from -40 °C to room temperature. Their output specific energy under a discharge power of 1 kW kg-1 is ca. 4 times larger than with a cell implementing the same carbon electrodes together with the binary [EMIm][BF4]0.5[FSI]0.5 liquid. Hence, this binary ionogel electrolyte concept paves the road for developing safe and flexible solid-state energy storage devices operating at subambient temperatures in extreme environments.

Date of online publication

26.05.2024

Pages (from - to)

e202400596-1 - e202400596-12

DOI

10.1002/cssc.202400596

URL

https://doi.org/10.1002/cssc.202400596

Comments

Article number: e202400596

Ministry points / journal

140