Posted in | Nanomaterials | Graphene

Energizer’s Molo Flake Graphite Passes Initial Testing for Creating Graphene Printing Ink

Energizer Resources Inc. is pleased to announce that UK-based Haydale Graphene Industries PLC, a global leader in the processing and application of graphene nanomaterials, has verified that the Company's Molo flake graphite has passed initial testing to be a viable source of graphene nanoplatelets for development of graphene inks for printed and flexible electronics.

Using Haydale's patent-pending plasma treatment process and ink formulation expertise, Molo flake graphite concentrate was successfully functionalized into graphene nanoplatelets, which were then used to successfully produce a prototype graphene ink.

Haydale's CEO Ray Gibbs, stated, "The purpose of these initial tests was to ascertain if Energizer's flake graphite concentrate could successfully create a graphene printing ink using our plasma functionalization technology. Initial test results were very positive, showing the Molo concentrate had improved bulk density, particle size distribution, surface area and enhanced sheet resistivity when compared to conventional carbon inks. The next stage of testing is to conduct performance testing but these initial tests would indicate an enhanced product. This is promising material".

The testing procedure involved processing flake concentrate produced from Energizer's pilot plant, which was then plasma treated and analyzed in accordance with Haydale standard operating procedures and conditions. Testing also revealed that the best performance results were achieved using Molo's smallest flake (-200 mesh), which is significant because -200 mesh material is the least saleable flake size. As per Company's February 5, 2015 news release titled, Energizer Resources Inc. Announces Positive Results of its Feasibility Study, only 21.1% of the Molo flake distribution is classified as -200 mesh (small flake), at a purity of 97.5% carbon that can be achieved with simple flotation alone. 78.9% of the Molo flake distribution is classified as medium, large and jumbo flake (+200 mesh to +48 mesh), with 46.4% specifically being classified as the premium large and jumbo flake (+80, +65 and +48 mesh).

The resulting data was evaluated against a myriad of metrics, including particle size distribution, tapped bulk density and titration (acid measurement).

Table 1 shows the resulting analysis of the plasma-functionalized powders, which passed 100% of Haydale's standard analysis procedures.

Table 1. Powder Data Summary

Energizer concentrate PSD Tapped bulk density Acid Number
D10 (µm) D50 (µm) D90 (µm) (kg/m3) (mg/KOH)
Raw 20.63 54.66 107.91 417 0.71
Processed 20.19 60.97 118.21 366 3.44

The ink was screen printed in accordance to Haydale's ISO 9001 quality control protocols. The ink was analyzed using a 4-point probe to measure electrical conductivity. Solids content and rheology were also measured. Table 2 shows typical improvements in normalized sheet resistivity of the Energizer graphene ink. These results exceeded those of standard carbon-only based inks available in the market today.

Table 2. Graphene Ink Data Summary

Energizer Ink Solids Viscosity Sheet Resistivity (normalized to 25 microns)
% Pa.s Ohm/sq. (avg.) Ohm/sq. (standard deviation)
INKENRG01 39.3 2.9-3.8 27.6 4.6

Conductive Graphene Inks

Graphene is a single-atom-thick sheet of flake graphite and is the lightest, thinnest and strongest material ever discovered in addition to being chemically stable, flexible and extremely conductive.

One of the first commercial products manufactured from graphene is conductive inks. A conductive ink results in a printed object that conducts electricity. These inks can be used to print circuits and other electronic components onto cheap, flexible materials such as paper, plastic and fabrics, for wearable electronics.

One example where printable graphene inks are now ready for commercial use is in low-cost radio-frequency identification (RFID) tags and wireless sensors, where the antennas can be flexible, environmentally friendly and cheaply mass-produced.


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