Molecular gate effects observed in fluoroalkylsilane self-assembled monolayers grafted on LiNi0.5Mn1.5O4cathodes: an application to efficient ion-exchange reactions

Charles-Blin, Youn; Todoki, Hitomi; Zettsu, Nobuyuki; Teshima, Katsuya

doi:10.1039/d1ma00426c

“…Li + ions are likely to be easily penetrating between fluoroalkyl chains (CF 2 ) due to their small ionic radius (≈90 pm, 6-coordination number) and are strongly trapped at CF bonds due to a high charge density of Li + ion. [58][59][60] Cs + ions, however, are less likely to penetrate between fluoroalkyl chains because of their larger ionic radius (≈181 pm). Also, coulombic attraction between Cs + ions and CF bonds is much weaker than between Li + ions and CF bonds because of a low charge density of Cs + ion.…”

Section: Resultsmentioning

confidence: 99%

Interfacial Ion‐Trapping Electrolyte‐Gated Transistors for High‐Fidelity Neuromorphic Computing

Jin

¹

,

Lee

²

,

Im

³

et al. 2022

Adv Funct Materials

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Li + electrolyte-gated transistors (EGTs) have received much attention as artificial synapses for neuromorphic computing. EGTs, however, have been still challenging to achieve long-term synaptic plasticity, which should be linearly and symmetrically controlled with the magnitude of electrical potential at the gate electrode. Herein, a fluoroalkylsilane (FAS) self-assembled monolayer (SAM) is introduced as a channel-electrolyte interlayer with the function of sequential ion-trapping in Li + EGTs. It is demonstrated that the retention of Li + ions can be enhanced, resulting in stable non-volatile channel conductance update with high fidelity, linearity, and symmetry in EGTs treated with FAS with 5 fluoroalkyl chains. Through investigating electrical analysis and chemical analysis, it is verified that fluoroalkyl chains enable the sequential ion-trapping at the channel-electrolyte interface by coulombic attraction between Li + ions and fluorocarbons. Simulations of artificial neural networks using 20 × 20 digits show FAS-treated EGTs are suitable as artificial synapses with an accuracy of 89.71% by identical gate pulses and 91.97% by non-identical gate pulses. A methodological approach is newly introduced for developing synaptic devices based on EGTs for neuromorphic computing with high fidelity.

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“…R/Si = 2 corresponds to a singlering polysiloxane structure with a low polymerization degree (4) and high-molar-mass linear polysiloxane (5). R/Si < 2 refers to network polymer (6), condensed ring (7), spiro (8), spherical ring (9) polysiloxanes with different crosslinking degrees and also T-shaped polysiloxane (10). [41] Such a variety of siloxane functionalization and molecular configuration implies special versatility and multiple energy applications (Scheme 2).…”

Section: Structure Of Siloxanementioning

confidence: 99%

Siloxane‐Based Organosilicon Materials in Electrochemical Energy Storage Devices

Wang

¹

,

Zhang

²

,

Li

³

et al. 2022

Angewandte Chemie

3

0

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Siloxane-based molecular material, by virtue of its unique chemical structure, thermal and electrochemical properties, has triggered tremendous research interest and sparked a revolution for energy storage in the past years. Siloxanes and their analogues are generally demonstrated to be more environmentally friendly, durable, and safer when employed to reconstruct the nano-micro surface structure of electrodes, separators, and their interfaces with electrolytes. To better understand the recent and comprehensive achievement of siloxane-based materials in energy storage, a systematic summary is necessary to provide important clues, aiming at achieving better electrochemical properties. In this Minireview, siloxane materials are presented comprehensively and systematically in terms of molecule design, functionality, and unique superiority for lithium-ion batteries and supercapacitors. The challenges, perspectives, and future directions of siloxane-based organosilicon materials are put forward for higher performance and wider application in electrochemical energy storage devices.

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“…For example, Zettsu and co‐workers reported that spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) cathodes modified by fluoroalkylsilane (FAS) monolayers showed improved C‐rate capabilities and high voltage durability. The FAS layer grafted on electrode surface effectively facilitated the Li + exchange reaction and eliminated the oxidative decomposition of free‐carbonate solvents by preferentially permeating solvated Li + /PF 6 − ions and blocking solvents from the cathode surface, respectively [10] …”

Section: Introductionmentioning

confidence: 99%

“…The FAS layer grafted on electrode surface effectively facilitated the Li + exchange reaction and eliminated the oxidative decomposition of freecarbonate solvents by preferentially permeating solvated Li + / PF 6 À ions and blocking solvents from the cathode surface, respectively. [10] In addition, the wide application of siloxanes as functional solvents, [11] co-solvents, [12] or additives [13] for electrolytes can promote the cell performance because they satisfy one or more of the following prerequisites. [14] Siloxanes display: 1) High ionic conductivity; 2) High thermal and chemical stability; [15] 3) Wide electrochemical window to maintain the stability of electrochemical performance over a wide voltage range.…”

Section: Introductionmentioning

confidence: 99%

Siloxane‐Based Organosilicon Materials in Electrochemical Energy Storage Devices

Wang

¹

,

Zhang

²

,

Li

³

et al. 2022

View full text Add to dashboard Cite

Siloxane-based molecular material, by virtue of its unique chemical structure, thermal and electrochemical properties, has triggered tremendous research interest and sparked a revolution for energy storage in the past years. Siloxanes and their analogues are generally demonstrated to be more environmentally friendly, durable, and safer when employed to reconstruct the nano-micro surface structure of electrodes, separators, and their interfaces with electrolytes. To better understand the recent and comprehensive achievement of siloxane-based materials in energy storage, a systematic summary is necessary to provide important clues, aiming at achieving better electrochemical properties. In this Minireview, siloxane materials are presented comprehensively and systematically in terms of molecule design, functionality, and unique superiority for lithium-ion batteries and supercapacitors. The challenges, perspectives, and future directions of siloxane-based organosilicon materials are put forward for higher performance and wider application in electrochemical energy storage devices.

show abstract

Molecular gate effects observed in fluoroalkylsilane self-assembled monolayers grafted on LiNi_0.5Mn_1.5O₄cathodes: an application to efficient ion-exchange reactions

Abstract: We demonstrated the role of fluoroalkylsilane (FAS) self-assembled monolayers in improving the high-voltage durability and C-rate capabilities of spinel LiNi0.5Mn1.5O4 (LNMO) cathodes. The influence of the cathode–electrolyte interface (CEI) layer...

Cited by 5 publications

References 41 publications

Interfacial Ion‐Trapping Electrolyte‐Gated Transistors for High‐Fidelity Neuromorphic Computing

Interfacial Ion‐Trapping Electrolyte‐Gated Transistors for High‐Fidelity Neuromorphic Computing

Siloxane‐Based Organosilicon Materials in Electrochemical Energy Storage Devices

Siloxane‐Based Organosilicon Materials in Electrochemical Energy Storage Devices

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