Book Description

The advancement of battery technology not only enables the creation of lighter and more durable electronic devices and long-range, long-life electric vehicles but also enhances the efficiency of sustainable clean energy storage, thereby mitigating the climate crisis of global warming. In 2019, lithium-ion batteries (LIB) technology was awarded the Nobel Prize in Chemistry, recognizing its significant improvement in our lives, and bringing us a rechargeable green world. The overarching research theme in this dissertation is the development of the next generation of electrochemical energy storage devices that provide high-capacity and can be fast-charged. This development requires the exploration of innovative fast-charging battery electrodes, which are the critical component that enables the battery to supply power rapidly. The bronze phase materials investigated in this dissertation meet this criterion as they contain large lithium-ion diffusion channels which enable fast-charging anode materials for LIBs. Comparative electrochemical studies conducted for bronze phase materials with the same stoichiometry, but different compositions (Mo3Nb2O14 vs W3Nb2O14), offer valuable insights into the design of next-generation, fast-charging materials for LIBs. A second material system, Mo4O11, also possesses properties appropriate for a fast-charging anode material for LIBs. Although the original open structure of Mo4O11 was altered during the first lithiation process, the newly formed layer-like structure was able to achieve both high capacity and fast-charging capability. These studies show that designing materials with rapid ion diffusion pathways and selecting transition metals with multielectron redox capability offer a promising way for simultaneously achieving both high energy and power density in next-generation electrochemical energy storage devices. Another important consideration which plays a vital role in obtaining high-performance batteries is the structure of the electrode. With the increase of mass loading or thickness of tape-cast electrodes, the energy density of batteries is enhanced due to the incorporation of more active materials. However, above a certain thickness, the increasing tortuosity of both ion and electron transport in traditional tape-cast electrodes compromises the power and offsets the benefits of increasing the amount of active material. Leveraging 3D printing technology, it is possible to design intricate 3D electrode structures that establish macroscopic ion-diffusion pathways, thereby breaking the limits achieved with thick tape-cast electrodes. The approach taken in this dissertation is based on obtaining ultra-high mass loading of manganese dioxide (MnO2) on 3D-printed graphene aerogel (3D MnO2/GA) electrodes. For these studies, sodium-ion batteries (SIB) were investigated as the combination of earth-abundant, high mass loading of MnO2 and sodium-ion battery technology creates a cost-effective solution for fulfilling the increasing demands of grid-level energy storage. An ether-based electrolyte was shown to improve the cycling stability of MnO2 compared to several other non-aqueous electrolytes. The feasibility of this approach to obtain both excellent areal energy and power density was demonstrated using a high mass loading TiO2-MnO2 sodium ion battery. The results of this research not only underscore the significance of using 3D-printed electrodes to achieve high energy and fast-charging next-generation electrochemical energy storage devices, but also the use of 3D-printed electrodes to achieve the high mass loading desired for reducing the manufacturing costs for batteries. A related research topic on the properties of pseudocapacitive vanadium dioxide (VO2) with 3D printed graphene aerogel scaffold was designed to evaluate the scalability of 3D electrode structures. The areal capacity of 3D VO2/GA was found to scale with the increase of both mass loading and electrode thickness with only minor sacrifice of gravimetric capacity. The device level scalability of 3D electrodes and the feasibility of using thick 3D electrodes in a commercial electrochemical energy storage device was demonstrated using a pseudo-solid silica-based ionogel material. The resulting sodium metal battery demonstrated scalable areal energy density using a coin cell. The results of this dissertation, which include both the design of advanced electrode materials and development of 3D electrodes, provide a basis for the development of the next generation of electrochemical energy storage devices that exhibit high-capacity and fast-charging.