Shape adaptable supercapacitors enabled by shrinkable polyaniline-bacterial cellulose nanofiber composites

• Main Author: Ang, Zi Hui
• Other Authors: Chen, Xiaodong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/141818
• Institution: Nanyang Technological University

Over the past few decades, the electrochemical energy storage system has been an indispensable fundamental in powering electronic devices for various purposes such as medical and communication uses. With the emergence of human-machine fusion for wearable and smart applications, electronics with stretchability and customizable shapes are required to be conformably integrated with the human body and in the smart robotic devices. With the ongoing evolution in the field of wearable electronics, immense emphasis and focus are in complementary changes and advancement in the properties of supercapacitors, such as their flexibility, stretchability, and customizable shapes. Even though there are immense effort and progression, further analysis and comprehension are required to enhance the present capability and customizability of supercapacitors. Hence, this research aims to assess the comprehensive finding of polyaniline (PANI)-bacterial cellulose nanofiber (BC) composite to meet the requirements of shape adaptable supercapacitors for mechanical tolerance. At the same time, a new strategy through filtration and self-release processes is developed to prepare shape-adaptable supercapacitors by using the shrinkable properties of PANI/BC. In this project, the synthesis of flexible and shrinkable PANI/BC composite electrode are carried out to achieve the aim in developing a method to fabricate shape-adaptable supercapacitors. It was found out that by increasing the mass ratio of PANI in the PANI/BC composite can promote the shrinking properties of the as-prepared film. The best electrochemical and mechanical as well as the cycling stability performance of the PANI-based electrodes was obtained at the optimal weight percent of 30% BC for PANI/BC composites electrode. The shrinkable and mechanical robust in PANI/BC (30%)-based composite electrode enables the fabrication of self-release and patternable supercapacitors with an areal capacitance of 4.96 mF cm-2 at a current density of 0.1 mA cm-2. In addition, the shapes of the PANI/BC supercapacitor can be tuned by filtration and self-release process, and the as-prepared shape adaptable supercapacitors with customizable stretchability can be instantly be transferred into different surfaces and conformed to the arbitrary curvature surfaces without compromising their electrochemical performance. Besides, the shape-adaptable supercapacitors with an auxetic honeycomb shape can also deliver a 99% capacitance retention after 10000 stretch-release test at a maximum strain of 400%, demonstrating their promising applications for bio-integrated and human-machine fields.