*Article* **Structural Design of Three-Dimensional Graphene**/**Nano Filler (Al2O3, BN, or TiO2) Resins and Their Application to Electrically Conductive Adhesives**

#### **Chia-Hsin Zhang <sup>1</sup> , Chia-Hung Huang <sup>2</sup> and Wei-Ren Liu 1,\***


Received: 7 October 2019; Accepted: 17 October 2019; Published: 18 October 2019

**Abstract:** In this study, we designed a three-dimensional structure of electrically conductive adhesives (ECAs) by adding three different kinds of nano filler, including BN, TiO2, and Al2O<sup>3</sup> particles, into a few-layered graphene (FLG)/polymer composite to avoid FLG aggregation. Three different lateral sizes of FLG (FLG3, FLG8, and FLG20) were obtained from graphite (G3, G8, and G20) by a green, facile, low-cost, and scalable jet cavitation process. The corresponding characterizations, such as Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM), verified the successful preparation of graphene flakes. Based on the results of four-point probe measurements, FLG20 demonstrated the lowest sheet resistance value of ~0.021 Ω/. The optimized ECAs' composition was a 60% solid content of FLG20 with the addition 2 wt.% of Al2O3. The sheet resistance value was as low as 51.8 Ω/, which was a reduction of 73% compared to that of pristine FLG/polymer. These results indicate that this method not only paves the way for the cheaper and safer production of graphene, but also holds great potential for applications in energy-related technologies.

**Keywords:** graphene; electrically conductive adhesive; fillers; TiO2; Al2O3; BN; resins
