Revealing Surfactant Effect of Trifluoromethylbenzene in Medium‐Concentrated PC Electrolyte for Advanced Lithium‐Ion Batteries

Abstract

Despite wide‐temperature tolerance and high‐voltage compatibility, employing propylene carbonate (PC) as electrolyte in lithium‐ion batteries (LIBs) is hampered by solvent co‐intercalation and graphite exfoliation due to incompetent solvent‐derived solid electrolyte interphase (SEI). Herein, trifluoromethylbenzene (PhCF3), featuring both specific adsorption and anion attraction, is utilized to regulate the interfacial behaviors and construct anion‐induced SEI at low Li salts’ concentration (<1 m). The adsorbed PhCF3, showing surfactant effect on graphite surface, induces preferential accumulation and facilitated decomposition of bis(fluorosulfonyl)imide anions (FSI−) based on the adsorption–attraction–reduction mechanism. As a result, PhCF3 successfully ameliorates graphite exfoliation‐induced cell failure in PC‐based electrolyte and enables the practical operation of NCM613/graphite pouch cell with high reversibility at 4.35 V (96% capacity retention over 300 cycles at 0.5 C). This work constructs stable anion‐derived SEI at low concentration of Li salt by regulating anions–co‐solvents interaction and electrode/electrolyte interfacial chemistries.

Electrolyte engineering and material modification for graphite‐based lithium‐ion batteries operated at low temperature

“…To circumvent the root shortcoming, its immediate sibling, propylene carbonate (PC), has been proposed as its convenient substitute due to a much lower melting point of −48.8°C. [51][52][53] Unfortunately, early research has revealed that the cointercalation of PC would inevitably occur and cause the exfoliation of graphite, leaving the failure of graphite in PC-based electrolyte. [54] With a deep understanding of the electrolyte, it is found that tuning the solvation sheath can mitigate this problem by introducing cosolvent.…”

Bifunctional Li2Se Mediator to Accelerate Sulfur Conversion and Lithium Deposition Kinetics in Lithium–Sulfurized Polyacrylonitrile Batteries

“…In addition, the conversion between sulfur and lithium sulfide unavoidably results in a massive volume change, further crumbling the cathode structure . To solve the abovementioned problems, a great variety of methods have been proposed, such as designing core–shell-structured cathode materials, − functional binders, − advanced electrolytes, − and so on. − Sulfurized polyacrylonitrile (SPAN) is a prospective sulfur cathode material because of its unique chemical structure and excellent electrochemical performance. , The low-order sulfur species (S 4 –S 2 ) are covalently bonded to the organic skeleton of pyrolyzed polyacrylonitrile chains, which helps mitigate the volume change during conversion. , More notably, it appears that no high-order polysulfides are observed in carbonate-based electrolytes, alleviating the shuttling effect . Unfortunately, the SPAN demonstrates sluggish reaction kinetics and poor cycling performance in ether-based electrolytes, which severely limits its application in practical Li–S batteries. , …”

Lithium‐Ion Batteries Containing Surfactants for the Protection of Graphite Anode against the Passivation Layer Byproducts

“…[6] Amongst the various classes of additives used, [13] surfactants owing to their specific spatial organization [14] emerge as promising candidates to alleviate the interfacial interactions that stem from the SEI layer formation. [15] Herein, we oriented the scope of the role of surfactants as protectors/stabilizers of the SEI in the presence or absence of (mineral) salts comprising the SEI (i. e., LiF, LiOH, Li 2 CO 3 , Li 2 O). The following three surfactants have been selected, namely, lithium dodecyl sulfate (LiDS), polyoxyethylene ether Forafac 1110D (LiF1110), and lithium perfluoro octanesulfonate Forafac 1185D (LiFOS).…”

“…The ideal amount of the selected additive likely depends on its function in the cell and the amount needed to obtain the desired effect (especially at the interface of electrode/electrolyte) without having a significant negative influence on other properties impacting the performance [6] . Amongst the various classes of additives used, [13] surfactants owing to their specific spatial organization [14] emerge as promising candidates to alleviate the interfacial interactions that stem from the SEI layer formation [15] …”