Nanocomposite Ionogel Electrolytes for Solid-State Batteries
Ionogels are composite solid-state electrolytes, in which ionic liquids are immobilized by gelling solid matrices. Compared to the organic solvents of traditional battery electrolytes, ionic liquids possess nonflammability, negligible vapor pressure, and high thermal stability, which not only enhances the safety but also elevates the high-temperature limit of battery operation. Moreover, when combined with a gelling matrix, ionic liquids form a solid-state electrolyte, which allows simplified packaging, streamlined manufacturing, and minimal risk of leakage. While a wide range of gelling matrices has been explored, ionogels based on nanostructured matrices are particularly promising since the high surface area of nanoscale materials promotes strong interactions with ionic liquids, resulting in enhanced ionic conductivity, mechanical properties, and thermal and electrochemical stability.
W. J. Hyun, C. M. Thomas, N. S. Luu, M. C. Hersam, “Layered heterostructure ionogel electrolytes for high-performance solid-state lithium-ion batteries,” Adv. Mater. 2021, 33, 2007864.
W. J. Hyun, C. M. Thomas, M. C. Hersam, “Nanocomposite ionogel electrolytes for solid-state rechargeable batteries,” Adv. Energy Mater. 2020, 10, 2002135.
W. J. Hyun, A. C. M. de Moraes, J.-M. Lim, J. R. Downing, K.-Y. Park, M. T. Z. Tan, M. C. Hersam, “High-modulus hexagonal boron nitride nanoplatelet gel electrolytes for solid-state rechargeable lithium-ion batteries,” ACS Nano 2019, 13, 9664–9672.
Compared to convention microfabrication methods, printing technologies allow direct pattering of depositing materials without extra time/material-consuming steps such as photolithography and etching. Thus, additive manufacturing based on printing processes facilitates the production of electronic devices with minimal materials waste and low cost. In addition, printing processes are compatible with roll-to-roll production formats and flexible substrates, which offers great promise for high-throughput manufacturing of flexible electronics. Due to these compelling advantages, significant research efforts have continuously sought to develop printed electronics solutions for diverse application areas.
W. J. Hyun, C. M. Thomas, L. E. Chaney, A. C. M. de Moraes, M. C. Hersam, “Screen-printable hexagonal boron nitride ionogel electrolytes for mechanically deformable solid-state lithium-ion batteries,” Nano Lett. 2022, 22, 5372–5378.
W. J. Hyun, E. B. Secor, C.-H. Kim, M. C. Hersam, L. F. Francis, C. D. Frisbie, “Scalable, self-aligned printing of flexible graphene micro-supercapacitors,” Adv. Energy Mater. 2017, 7, 1700285.
W. J. Hyun, E. B. Secor, G. A. Rojas, M. C. Hersam, L. F. Francis, C. D. Frisbie, “All-printed, foldable organic thin-film transistors on glassine paper,” Adv. Mater. 2015, 27, 7058–7064.
Solution-Processable 2D Materials
Liquid-phase exfoliation is a top-down approach to produce 2D materials from bulk materials that are a layered structure with strong in-plane bonds and weak van der Waals interactions between layers. When ultrasonic waves or shear forces are applied to a solution containing bulk materials, the mechanical forces break the van der Waals interactions and isolate 2D layers from the bulk materials. This liquid-phase exfoliation approach facilitates scalable and low-cost production of 2D materials. Moreover, as-obtained 2D materials in the form of dispersions can be readily utilized for various solution-processing methods such as screen/inkjet/aerosol-jet printing and spray/spin/dip coating.
W. J. Hyun, L. E. Chaney, J. R. Downing, A. C. M. de Moraes, M. C. Hersam, “Printable hexagonal boron nitride ionogels,” Faraday Discuss. 2021, 227, 92–104.
W. J. Hyun, E. B. Secor, M. C. Hersam, “Printable graphene inks stabilized with cellulosic polymers,” MRS Bull. 2018, 43, 730–732.
W. J. Hyun, E. B. Secor, M. C. Hersam, C. D. Frisbie, L. F. Francis, “High-resolution patterning of graphene by screen printing with a silicon stencil for highly flexible printed electronics,” Adv. Mater. 2015, 27, 109–115.