20.500.12556/DKUM-92414 Electrochemical capacitance of CNF–Ti3C2Tx MXene-based composite cryogels in different electrolyte solutions for an eco-friendly supercapacitor Cellulose nanofibrils (CNFs) are promising materials for flexible and green supercapacitor electrodes, while Ti3C2Tx MXene exhibits high specific capacitance. However, the diffusion limitation of ions and chemical instability in the generally used highly basic (KOH, MXene oxidation) or acidic (H2SO4, CNF degradation) electrolytes limits their performance and durability. Herein, freestanding CNF/MXene cryogel membranes were prepared by deep freeze-casting (at −50 and −80 ◦C), using different weight percentages of components (10, 50, 90), and evaluated for their structural and physico-chemical stability in other less aggressive aqueous electrolyte solutions (Na2/Mg/Mn/K2-SO4, Na2CO3), to examine the influence of the ions transport on their pseudocapacitive properties. While the membrane prepared with 50 wt% (2.5 mg/cm2 ) of MXene loading at −80 ◦C shrank in a basic Na2CO3 electrolyte, the capacitance was performed via the forming of an electroactive layer on its interface, giving it high stability (90% after 3 days of cycling) but lower capacitance (8 F/g at 2 mV/s) than in H2SO4 (25 F/g). On the contrary, slightly acidic electrolytes extended the cations’ transport path due to excessive but still size-limited diffusion of the hydrated ions (SO4 2− > Na+ > Mn2+ > Mg2+) during membrane swelling, which blocked it, reducing the electroactive surface area and lowering conductivities (<3 F/g). cellulose nanofibrils Ti3C2Tx MXene freeze-casting aqueous electrolytes physico-chemical properties electric double layer pseudocapacitance nanofibrilirana celuloza zamrzovanje-ulivanje vodni elektroliti fizikalno-kemijske lastnosti električna dvojna plast psevdokapacitivnost true false true MDPI Angleški jezik Slovenski jezik https://www.mdpi.com/journal/gels © 2025 by the authors Članek v reviji 2025-04-07 11:59:46 2025-04-07 11:59:46 2026-01-26 12:14:04 0000-00-00 00:00:00 2025 0 0 24 str. iss. 4, [article no.] 265 Vol. 11 April 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-02-18 2025-03-31 2025-04-03 677.46:620.3 231603459 10.3390/gels11040265 2310-2861 gels-11-00265.pdf gels-11-00265.pdf 1 BCA1F5CCCE95C56B9FBF7984453C765C ef4b1dfa6be428d3febf789aafed1e27974d9a079ec36e1a8887ac2c253832a7 5254da5a-139a-11f0-9c98-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=190054 https://www.mdpi.com/2310-2861/11/4/265 0 59cd04ea-1470-11f0-b4ef-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=190104 Fakulteta za strojništvo 0 0 0