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Abstract The proliferation and miniaturization of portable electronics require energy‐storage devices that are simultaneously compact, flexible, and amenable to scalable manufacturing. In this work, mechanically flexible micro‐supercapacitor arrays are demonstrated via sequential high‐speed screen printing of conductive graphene electrodes and a high‐temperature hexagonal boron nitride (hBN) ionogel electrolyte. By combining the superlative dielectric properties of 2D hBN with the high ionic conductivity of ionic liquids, the resulting hBN ionogel electrolyte enables micro‐supercapacitors with exceptional areal capacitances that approach 1 mF cm−2. Unlike incumbent polymer‐based electrolytes, the high‐temperature stability of the hBN ionogel electrolyte implies that the printed micro‐supercapacitors can be operated at unprecedentedly high temperatures up to 180 °C. These elevated operating temperatures result in increased power densities that make these printed micro‐supercapacitors particularly promising for applications in harsh environments such as underground exploration, aviation, and electric vehicles. The combination of enhanced functionality in extreme conditions and high‐speed production via scalable additive manufacturing significantly broadens the technological phase space for on‐chip energy storage.
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Centrifuge‐Free Separation of Solution‐Exfoliated 2D Nanosheets via Cross‐Flow Filtration
Abstract Solution‐processed graphene is a promising material for numerous high‐volume applications including structural composites, batteries, sensors, and printed electronics. However, the polydisperse nature of graphene dispersions following liquid‐phase exfoliation poses major manufacturing challenges, as incompletely exfoliated graphite flakes must be removed to achieve optimal properties and downstream performance. Incumbent separation schemes rely on centrifugation, which is highly energy‐intensive and limits scalable manufacturing. Here, cross‐flow filtration (CFF) is introduced as a centrifuge‐free processing method that improves the throughput of graphene separation by two orders of magnitude. By tuning membrane pore sizes between microfiltration and ultrafiltration length scales, CFF can also be used for efficient recovery of solvents and stabilizing polymers. In this manner, life cycle assessment and techno‐economic analysis reveal that CFF reduces greenhouse gas emissions, fossil energy usage, water consumption, and specific production costs of graphene manufacturing by 57%, 56%, 63%, and 72%, respectively. To confirm that CFF produces electronic‐grade graphene, CFF‐processed graphene nanosheets are formulated into printable inks, leading to state‐of‐the‐art thin‐film conductivities exceeding 104S m−1. This CFF methodology can likely be generalized to other van der Waals layered solids, thus enabling sustainable manufacturing of the diverse set of applications currently being pursued for 2D materials.
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- PAR ID:
- 10419179
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 35
- Issue:
- 24
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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