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Carboxylic acid functionalized cellulose nanocrystals have been obtained from biomass and evaluated as aqueous, environmentally sustainable alternatives to conventional polyvinylidene difluoride binders for cathodes of lithium-ion batteries. 

Cross-flow filtration using porous ceramic membranes enables high-throughput and energy-efficient production of printable graphene inks for high-performance flexible electronic applications. 

Abstract Graphite is a commonly used raw material across many industries and the demand for high‐quality graphite has been increasing in recent years, especially as a primary component for lithium‐ion batteries. However, graphite production is currently limited by production shortages, uneven geographical distribution, and significant environmental impacts incurred from conventional processing. Here, an efficient method of synthesizing biomass‐derived graphite from biochar is presented as a sustainable alternative to natural and synthetic graphite. The resulting bio‐graphite equals or exceeds quantitative quality metrics of spheroidized natural graphite, achieving a RamanI_D/I_Gratio of 0.051 and crystallite size parallel to the graphene layers (L_a) of 2.08 µm. This bio‐graphite is directly applied as a raw input to liquid‐phase exfoliation of graphene for the scalable production of conductive inks. The spin‐coated films from the bio‐graphene ink exhibit the highest conductivity among all biomass‐derived graphene or carbon materials, reaching 3.58 ± 0.16 × 10⁴S m⁻¹. Life cycle assessment demonstrates that this bio‐graphite requires less fossil fuel and produces reduced greenhouse gas emissions compared to incumbent methods for natural, synthesized, and other bio‐derived graphitic materials. This work thus offers a sustainable, locally adaptable solution for producing state‐of‐the‐art graphite that is suitable for bio‐graphene and other high‐value products. 

Abstract Liquid phase exfoliation (LPE) of graphene is a potentially scalable method to produce conductive graphene inks for printed electronic applications. Among LPE methods, wet jet milling (WJM) is an emerging approach that uses high‐speed, turbulent flow to exfoliate graphene nanoplatelets from graphite in a continuous flow manner. Unlike prior WJM work based on toxic, high‐boiling‐point solvents such as n‐methyl‐2‐pyrollidone (NMP), this study uses the environmentally friendly solvent ethanol and the polymer stabilizer ethyl cellulose (EC). Bayesian optimization and iterative batch sampling are employed to guide the exploration of the experimental phase space (namely, concentrations of graphite and EC in ethanol) in order to identify the Pareto frontier that simultaneously optimizes three performance criteria (graphene yield, conversion rate, and film conductivity). This data‐driven strategy identifies vastly different optimal WJM conditions compared to literature precedent, including an optimal loading of 15 wt% graphite in ethanol compared to 1 wt% graphite in NMP. These WJM conditions provide superlative graphene production rates of 3.2 g hr⁻¹with the resulting graphene nanoplatelets being suitable for screen‐printed micro‐supercapacitors. Finally, life cycle assessment reveals that ethanol‐based WJM graphene exfoliation presents distinct environmental sustainability advantages for greenhouse gas emissions, fossil fuel consumption, and toxicity. 

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. 

Abstract Soft materials with reversible electrical and mechanical properties are critical for the development of advanced bioelectronics that can distinguish between different rates of applied strain and eliminate performance degradation over many cycles. However, the current paradigm in mechano‐electronic devices involves measuring changes in electrical current based on the accumulation of strain within a conductive material that alters the geometry through which electrons flow. Attempts have been made to incorporate soft materials like liquid metals and concentrated solutions of conjugated polymers and salts to overcome materials degradation but are limited in their ability to detect changes in the rate of the applied strain. Herein, the anisotropic electrical performance of a soft semiconducting composite prepared with silver‐coated microspheres dispersed within a swollen copolymer gel is demonstrated. This composite exhibits an electrical response proportional to the magnitude of the applied shear force to enable a rate‐of‐strain dependent conductivity. Furthermore, a 100‐fold increase in the conductivity of the composite is observed when the electric field is oriented parallel to the flow direction. This improvement in the electrical response can be attributed to the enhanced alignment of microspheres in viscoelastic media and can be leveraged in the development of mechanically responsive electronic devices.