Ergimiş tuz aşındırmasıyla sentezlenen Klor-Termine MXenelerde elektrolit-bağımlı lityum interkalasyonu

Year 2025, Volume: 14 Issue: 4, 1339 - 1351, 15.10.2025

Esra Kilavuz

Abstract

MXeneler, geniş uygulama alanlarına sahip iki boyutlu malzemelerdir. Bu malzemelerin elektrokimyasal özellikleri, yüzeylerindeki sonlanma grupları (fonksiyonel gruplar) tarafından büyük ölçüde belirlenir. Geleneksel olarak, MXene sentezinde hidroflorik asit (HF) kullanılır ve bu yöntemle yüzeyde genellikle-O, -F ve -OH gibi sonlanma grupları oluşur. Ancak bu gruplar, MXene'nin iletkenliğini, kararlılığını, elektrokimyasal davranışını ve kimyasal reaktivitesini sınırlayabilir. Bu çalışmada, geleneksel HF-aşındırma metodu yerine kontrollü klor terminasyonu sağlayan ZnCl₂ kullanılarak ergimiş tuz aşındırma yöntemiyle çok katmanlı Ti₃C₂Cl₂ MXeneler sentezlenmiştir. Klor-terminasyonlu bu MXenelerin (MS-Ti₃C₂Cl₂) lityum-iyon interkalasyon davranışı, DMSO, PC ve ACN organik elektrolitlerinde üç elektrotlu Swagelok hücre düzeneği kullanılarak sistematik olarak incelenmiştir. Elektrokimyasal ölçümler, elektrolit bileşiminin interkalasyon dinamiği üzerinde belirleyici bir etkiye sahip olduğunu ortaya koymuştur. PC elektroliti, tam desolvasyon yoluyla psödokapasitif Li⁺ depolanmasını sağlarken, DMSO yüksek Coulomb verimliliği (~%100) ve karmaşık yük depolama kinetiği sergilemiştir. Buna karşılık, ACN'de solvatlı Li⁺ iyonlarının ko-interkalasyonu performans düşüşüne yol açmıştır. Kinetik analiz, b-değeri kantifikasyonu kullanılarak gerçekleştirilmiş ve DMSO için difüzyon-kontrollü davranış (b = 0,663), ACN için ise yüzey-dominant kapasitif davranış (b=0,884) gözlemlenmiştir. Bu bulgular, yüksek performanslı enerji depolama uygulamaları için MXene-tabanlı elektrotların optimizasyonunda terminasyon kimyası ve çözgen seçiminin önemini vurgulamaktadır.

Keywords

MXene , organik elektrolitler , LIBs , eriyik tuz aşındırma , Li interkalasyonu

Electrolyte-dependent lithium intercalation in Chlorine-Terminated MXenes synthesized via molten salt etching

Abstract

MXenes are two-dimensional materials with a wide range of applications. The electrochemical properties of these materials are largely determined by their surface terminations (functional groups). Traditionally, hydrofluoric acid (HF) is used for MXene synthesis, which typically results in -O, -F, and -OH surface terminations. However, these groups can limit the MXene's conductivity, stability, electrochemical behavior, and chemical reactivity. In this study, we synthesized multilayer Ti₃C₂Cl₂ MXenes via a molten salt etching route using ZnCl₂, a method that enables the controlled introduction of chlorine surface terminations instead of conventional HF-based approaches. We systematically investigated the lithium-ion intercalation behavior of these chlorine-terminated MXenes (MS-Ti₃C₂Cl₂) in organic electrolytes—DMSO, PC, and ACN—employing a three-electrode Swagelok cell configuration. Electrochemical analysis showed that electrolyte composition strongly affects Li⁺ intercalation behavior. PC enabled pseudocapacitive storage via full desolvation, while DMSO offered high Coulombic efficiency (~100%) with mixed kinetics. ACN caused solvated Li⁺ co-intercalation and poor performance. b-value analysis indicated diffusion-controlled behavior in DMSO (b = 0.663) versus capacitive dominance in ACN (b = 0.884). These results highlight the critical role of termination chemistry and solvent choice in optimizing MXene electrodes for advanced energy storage with customized interfacial properties.

Keywords

MXene , Li intercalation , organic electrolytes , LIBs , molten salt etching

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