Cyclic production of biocompatible few-layer graphene ink with in-line shear-mixing for inkjet-printed electrodes and Li-ion energy storage

Abstract

The scalable production of two-dimensional (2D) materials is needed to accelerate their adoption to industry. In this work, we present a low-cost in-line and enclosed process of exfoliation based on high-shear mixing to create aqueous dispersions of few-layer graphene, on a large scale with a Yw ~ 100% yield by weight and throughput of ϕ ~ 8.3 g h−1. The in-line process minimises basal plane defects compared to traditional beaker-based shear mixing which we attribute to a reduced Reynolds number, Re ~ 105. We demonstrate highly conductive graphene material with conductivities as high as σ ∼ 1.5 × 104 S m−1 leading to sheet-resistances as low as Rs ∼ 2.6 Ω □−1 (t ∼ 25 μm). The process is ideal for formulating non-toxic, biocompatible and highly concentrated (c ∼ 100 mg ml−1) inks. We utilise the graphene inks for inkjet printable conductive interconnects and lithium-ion battery anode composites that demonstrate a low-rate lithium storage capability of 370 mAh g−1, close to the theoretical capacity of graphite. Finally, we demonstrate the biocompatibility of the graphene inks with human colon cells and human umbilical vein endothelial cells at high c ∼ 1 mg ml−1 facilitating a route for the use of the graphene inks in applications that require biocompatibility at high c such as electronic textiles.

High-Mobility Flexible Transistors with Low-Temperature Solution-Processed Tungsten Dichalcogenides

“…Plotting the flake aspect ratio (AR, L/t) versus t in Figure 1e shows maximum AR values of 309, 326, and 177 for MoS 2 , WS 2 , and WSe 2 flakes, respectively, with means of 102, 132, and 70. These values are significantly higher than ARs achieved with LPE by ultrasonication (AR ≈ 10−40), 8,27 shear mixing (AR ≈ 4−40, Supplementary Note 1), cyclic shear mixing (AR ≈ 60) 28 or microfluidization (AR ≈ 50). 29 AR > 40 is required to make conformal flake-to-flake junctions to minimize the junction resistance to improve the device performance.…”

Sustainable Upcycling of Spent Electric Vehicle Anodes into Solution-Processable Graphene Nanomaterials

“…To remove these, the as-prepared dispersions were centrifuged at RCF = 115g for 20 min, following a similar approach recently described for biocompatible few-layer graphene inks. 30 As these formulations contain thicker nanoplatelets, we refer to the inks as graphene-related material (Grm) to distinguish them from the few-layer graphene dispersions formulated at RCF = 243g. The ink concentration was increased to above 1 g/L by exfoliating spent graphite anode material at C i = 50 g/L and using a surfactant concentration, C i /C sc = 100, corresponding to the peak C gr shown in Figure 3.…”

“…This suggests that the graphite mass is dominated by a small number of poorly exfoliated particles. To remove these, the as-prepared dispersions were centrifuged at RCF = 115 g for 20 min, following a similar approach recently described for biocompatible few-layer graphene inks . As these formulations contain thicker nanoplatelets, we refer to the inks as graphene-related material (Grm) to distinguish them from the few-layer graphene dispersions formulated at RCF = 243 g .…”

Sustainable up-cycling of spent electric vehicle anodes into solution processable graphene nanomaterials

“…To remove these, the as-prepared dispersions were centrifuged at a RCF = 115g for 20 minutes, following a similar approach recently described for biocompatible few-layer graphene inks. 30 As these formulations contain thicker nanoplatelets, we refer to the inks as graphene-related material (Grm) to distinguish them from the few-layer graphene dispersions formulated at RCF = 243g.…”