Bacterial-Cellulose-Reinforced Graphite Nanoplate Films for Electromagnetic Interference Shielding, Heat Conduction, and Joule Heating

With the flourishing development of wireless communication, there is an urgent need for flexible and robust materials with excellent thermal conductivity (TC) and electromagnetic interference (EMI) shielding performance through simple and green preparation. In this work, we efficiently prepared bacterial-cellulose-reinforced graphite nanoplate (BC-GNP) composite films by the vacuum filtration of BC/GNP mixture dispersions. Compared with the pure GNP film with a loose and disordered structure, the BC-GNP composite showed a highly aligned and compact “brick-and-mortar” structure. Benefiting from the unique structure, the resultant BC-GNP with 20 wt % BC (20%BC) exhibited a high tensile strength of 47.3 ± 1.8 MPa and an electrical conductivity of 76.9 ± 3.3 S/cm. As expected, the 20%BC showed excellent EMI shielding effectiveness (EMI SE) of 36.4 dB and a specific EMI SE (SSE/t) value of 8860 ± 400 dB·cm2/g with a thickness of 38 ± 1 μm. The in-plane TC and anisotropy index could reach up to 80.2 ± 6.4 W/mK and 73 ± 3, respectively. The 20%BC also exhibited a satisfactory Joule heating performance of 139 °C at a voltage of 6 V. More importantly, the 20%BC possessed a biodegradable property, which would completely degrade after 5 days. Thus, this work provides a strategy to facilely prepare biodegradable, high-performance, and multifunctional materials for wearable devices.