UC Santa Cruz

With the ever-increasing demand for portable electronic technologies, the development of new electrochemical energy storage (EES) devices such as supercapacitors and batteries that could withstand extreme conditions is urgently needed. Currently, the commercially available EES devices often suffer sever loss of energy and power densities under extreme operating temperatures and application of external mechanical deformation. These extreme conditions normally posed challenges on EES devices, limiting their applications. The electrodes are determined to play an important role in the overall performance of the EES devices. The specific capacity, rate capability, and energy and power densities of EES devices all depend on the electrode used. This dissertation covers different design and optimization strategies to enhance the performance of EES devices and broaden their application to extreme operating conditions.The 1st Chapter presents the background for energy storage, the different types of EES devices’ electrode, and their applications at extreme conditions. The goal of this section is to create a general framework for these two key research directions in energy storage. The 2nd Chapter focuses on enhancing the surface chemistry of the porous electrode for low temperature supercapacitors. In this chapter we explored how introducing nitrogen dopant can increase capacitance and achieve high retention even at low operating temperature of -40°C. The 3rd Chapter addresses the challenge of mechanical integrity in 3D printed carbon aerogel electrodes which limit its practical application. In this chapter, we present a new ink formulation that enhances the mechanical properties of the resulting carbon aerogels. The 4th Chapter discusses the impact of manganese oxide polymorphism on electrochemical performance in aqueous and non-aqueous system. In this chapter, we aim to address how the structural characteristics of electrodeposited manganese oxide—specifically its crystal phase, crystallinity, and crystal size—affect its electrochemical performance in energy storage devices like batteries and supercapacitors. Lastly, 5th Chapter provides overview of challenges and perspective research directions for the advancement of EES devices.