An electrolyte additive capable of scavenging HF and PF5 enables fast charging of lithium-ion batteries in LiPF6-based electrolytes

Han, Jung‐Gu; Jeong, Minyoung; Kim, Koeun; Park, Chanhyun; Sung, Chang Kyung; Bak, Dae Won; Kim, Kyung Ho; Jeong, Kyeong-Min; Choi, Nam‐Soon

doi:10.1016/j.jpowsour.2019.227366

Cited by 142 publications

(93 citation statements)

References 31 publications

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“…Although most scavenger additives have been tested in LIBs, their mode of operation should be identical in combination with LMBs. (Trimethylsilyl)isothiocyanate (TMSNCS) has a high electron donating ability and scavenges PF 5 and HF in LiPF 6 based electrolytes [53]. Phosphite containing compounds such as tris(2,2,2-trifluoethyl) phosphite (TTFP) and trimethyl phosphite are excellent PF 5 scavengers, due to being highly nucleophilic, hence acting as Lewis bases [54,55].…”

Section: In-situ Sei With Additives/electrolytementioning

confidence: 99%

Current status and future perspectives of lithium metal batteries

Varzi

Thanner

Scipioni

et al. 2020

Journal of Power Sources

127

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Section: In-situ Sei With Additives/electrolytementioning

confidence: 99%

Current status and future perspectives of lithium metal batteries

Varzi

Thanner

Scipioni

et al. 2020

Journal of Power Sources

127

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“…The discoloration of the standard electrolyte is because H 2 O (or HF) aggravates the decomposition of lithium salt (LiPF 6 ) to produce PF 5 , which catalyzes the ring-opening polymerization of cyclic solvent (EC) to produce a PEO-like polymer and CO 2 (Figure S2), and discolor the electrolyte. , Figure c shows the 19 F NMR spectra of standard electrolyte. The peaks around −72, −75, and −150 ppm represent PF 6 – , PO 3 F 2– , and HF, respectively. − The reformulated electrolyte with BTA additive shows two strong characteristic peaks of PF 6 – (Figure d), indicating that the BTA additive can remove H 2 O and inhibit the decomposition of LiPF 6 . Notably, a weak PO 3 F 2– peak located at −74 ppm indicates that some LiPF 6 was decomposed to produce a small amount of HF, which was then removed by the BTA additive .…”

Section: Resultsmentioning

confidence: 99%

“…Based on the above discussion and the results of previous related literature, the removal of H 2 O and HF molecules in the electrolyte is mainly achieved by their complexation with electron-donating sites such as siloxane (Si–O) and silazane (Si–N) functional groups. The intrinsic chemical reactivity of Si–O and Si–N functional groups includes the following two aspects: (1) lone pairs electrons on oxygen and nitrogen can easily bind with H + by acid–base interactions; (2) the electron-donating TMS group can combine F – (or OH – ) anion and form a stable intermediate. ,, Because a BTA molecule has both Si–O and Si–N bonds, the mechanism of H 2 O and HF molecules’ removal by the BTA additive may be achieved through two pathways, as shown in Figure b,c. Therefore, the BTA additive can spontaneously bind H 2 O and HF molecules and stabilizes the LiPF 6 -based electrolyte.…”

Section: Resultsmentioning

confidence: 99%

Multifunctional Electrolyte Additive Stabilizes Electrode–Electrolyte Interface Layers for High-Voltage Lithium Metal Batteries

Liu

Jiang

et al. 2021

ACS Appl. Mater. Interfaces

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A lithium metal anode and high nickel ternary cathode are considered viable candidates for high energy density lithium metal batteries (LMBs). However, unstable electrode–electrolyte interfaces and structure degradation of high nickel ternary cathode materials lead to serious capacity decay, consequently hindering their practical applications in LMBs. Herein, we introduced N,O-bis(trimethylsilyl) trifluoro acetamide (BTA) as a multifunctional additive for removing trace water and hydrofluoric acid (HF) from the electrolyte and inhibiting corrosive HF from disrupting the electrode–electrolyte interface layers. Furthermore, the BTA additive containing multiple functional groups (C–F, Si–O, Si–N, and CN) promotes the formation of LiF-rich, Si- and N-containing solid electrolyte interfacial films on a lithium metal anode and LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode surfaces, thereby improving the electrode–electrolytes interfacial stability and mitigating the capacity decay caused by structural degradation of the layered cathode. Using the BTA additive had tremendous benefits through modification of both anode and cathode surface layers. This was demonstrated using a Li||NMC811 metal battery with the BTA electrolyte, which exhibits remarkable cycling and rate performances (122.9 mA h g–1 at 10 C) and delivers a discharge capacity of 162 mA h g–1 after 100 cycles at 45 °C. Likewise, this study establishes a cost-effective approach of using a single additive to improve the electrochemical performance of LMBs.

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“…One of the reasons for the OCP drop was the influence of the undesired reactions, including electrolyte decomposition. This is because electrolyte decomposition occurs through electron transferring from electrolyte to cathode, thereby leading to a potential drop of the electrode 35,47,48 . This means that decomposition of electrolyte is well mitigated in the cell controlled with TEAB, even at elevated temperatures.…”

Section: Resultsmentioning

confidence: 99%

Triethanolamine borate as a surface stabilizing bifunctional additive for Ni‐rich layered oxide cathode

et al. 2020

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Summary Ni‐rich cathode materials have been receiving substantial highlight because of its large specific capacity, however, they suffer from inferior cycling results owing to occurring undesired reactions in the cell. Herein, triethanolamine borate (TEAB), containing borate and ethanolamine groups, is proposed as a functional additive because it spontaneously suppresses electrolyte decomposition while inhibiting Ni dissolution in Ni‐rich cathodes. The electrochemical oxidation of TEAB first generates borate‐based cathode‐electrolyte interphases for the Ni‐rich cathode, which effectively suppress the electrolyte decomposition. A cell controlled with TEAB showed a greatly decreased internal pressure, which improved the safety performance of the cell. Notably, even the inclusion of 0.1% TEAB in the cell markedly increased the cycling performance from 32.0% to 63.2%. Cells cycled with TEAB showed stable retention rate after 100 cycles at high temperature. Results of high‐temperature storage of the cells confirmed improvements as changes in the open‐circuit potentials, thickness of the cell, and the recovery rate for specific capacity. TEAB is also efficient for suppressing Ni dissolution because TEAB selectively scavenges fluoride species by a chemical scavenging reaction. The cell evaluated with TEAB‐containing electrolyte exhibited a releasing 140.3 ppm of dissolved Ni, whereas the cell evaluated with bare electrolyte released 643.6 ppm.

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An electrolyte additive capable of scavenging HF and PF5 enables fast charging of lithium-ion batteries in LiPF6-based electrolytes

Cited by 142 publications

References 31 publications

Current status and future perspectives of lithium metal batteries

Current status and future perspectives of lithium metal batteries

Multifunctional Electrolyte Additive Stabilizes Electrode–Electrolyte Interface Layers for High-Voltage Lithium Metal Batteries

Triethanolamine borate as a surface stabilizing bifunctional additive for Ni‐rich layered oxide cathode

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