Analyzing Electrolyte Degradation via Chemical, Thermal, and Electrochemical Methods

Sodium-ion battery technology is a promising and sustainable solution to the dominate lithium-ion battery. Limitations in the availability and cost of lithium are concerns for current commercialized battery technology. A battery system is comprised of three major components: an anode, a cathode, and an electrolyte. The presented work focuses on the identification of viable electrolytes based on performance and degradation studies in sodium based electrolytes. Electrolyte reactions play a critical role in the stability of the battery, and a better understanding of these products in the sodium system will lead to improved stability. Fundamental studies of chemical, thermal, and electrochemical stability have been performed in the presence of selected additives. Our current results show that water concentration plays a significant role in degradation, as samples with more water contained larger amounts of side reaction products, including the formation of hydrofluoric acid

Non-Aqueous Electrolytes for Na-Ion Batteries

Since their commercialization in the 1990s lithium ion batteries (LIBs) are the prevalent energy storage device for portable electronics. However, as energy storage technologies improve scientists are looking beyond LIBs to meet future demands. Unlike lithium, sodium supplies are virtually unlimited and evenly distributed worldwide which greatly reduces cost and increases availability of raw materials. However, before sodium-ion batteries (NIBs) can be successfully implemented there are several challenges which must be met, including the optimization of electrolyte systems. Titanium dioxide nanotubes (TiO2 NT) grown on titanium metal have been shown to reversibly incorporate sodium ions at room temperature and by investigating electrolyte systems we hope to improve electrochemical behavior and increase battery safety of NIBs

Nanostructured Niobium Oxide for Sodium and Potassium-Ion Batteries

The battery is a key component to the development and implementation of renewable energy. Wind and sunlight are intermittent energy sources. Batteries offer the ability to store this energy and distribute it during high demand. Currently, Lithium-ion battery technology leads the market in performance. However, lithium-based technologies face challenges in availability and cost. The ability to use sodium or potassium as an alternative ion source could negate these challenges. However, sodium and potassium-ion batteries are inherently difficult to produce due to their larger ionic size, weight, and lower mobility. Finding electrode materials that are capable of coping with these properties is a challenge. This study experiments on the use of nano-channeled niobium oxide (NCNO) as an anode for sodium and potassium-ion batteries. As a ceramic, niobium oxide is a prospective candidate as an electrode material. The porous nanostructure of NCNO provides more surface area for electrochemical reactions to take place. Additionally, amorphous NCNO’s can be crystallized to change the kinetics and cell performance of the battery. Samples of NCNO were electrochemically tested in sodium and potassium-ion half-cells. Through this work we will learn about the electrochemical performance of this material based on the rate capability, life cycle, and capacity observed

3D Li-Ion Batteries Through Advanced Manufacturing

The growing demand for secure storage systems to improve energy and power systems has prompted innovative research into the advancement of material systems and devices. While lithium-ion batteries currently dominate as the primary power source for portable electronics, they face limitations in meeting the requirements for sustainable energy applications like electric vehicles and renewable energy storage. Solid-state batteries offer a potential solution by addressing the drawbacks of traditional lithium-ion cells. Unlike liquid electrolytes, solid electrolytes demonstrate high thermal stability, reducing the risk of fire or explosion at high temperatures. Additionally, solid-state batteries achieve higher energy density per unit area due to their compact size, with potential energy density up to ten times greater than that of similarly sized lithium-ion batteries. This study focuses on utilizing Garnet type Lithium Lanthanum Zirconium Oxide (LLZO) as the solid electrolyte material due to its high ionic conductivity and stability. The objective of the project is to develop an advanced manufacturing process for a solid LLZO electrolyte and compare the performance of different printed geometries in battery cells

Oxide-Coated Titanium Dioxide Nanotube Anodes in Sodium-Ion Batteries

Although lithium-ion batteries are commonly used for energy storage, the cost and availability of source materials have accelerated research in alternative sodium-ion batteries (NIBs). However, the energy storage capacity and cycle life of NIBs must be increased before becoming commercially viable. One approach to improving NIB performance is to stabilize the solid electrolyte interphase (SEI). The SEI develops when the electrolyte and electrodes react, forming an additional layer through which ions must diffuse. An unstable SEI layer can cause irreversible capacity loss, but an artificial SEI layer may lower capacity loss and increase stability over many cycles. Coating the anode surface with thin layers of different materials has been shown to stabilize the SEI. This work studies the effect of coating anatase and amorphous titanium dioxide nanotube anodes with thin films of aluminum oxide and additional titanium dioxide via atomic layer deposition (ALD). The capacity, cycle life, and role of surface energy will be investigated as a function of the thickness of these oxide coatings

Hydrothermal Synthesis of Titanate Nano-Structures for use as Anode Material in Sodium-Ion Batteries

Lithium-ion batteries (LIBs) have been successful in a wide variety of applications from cell phones to electric cars, but concerns about scarcity and the price of lithium are steering research toward alternative materials for rechargeable batteries. Due to the abundance of sodium and its chemical and electrochemical similarities to lithium, sodium-ion batteries (NIBs) present one likely alternative to LIBs. Some challenges remain in the development of NIBs, especially in the development of suitable anode materials. As a highly stable, inexpensive, nontoxic, and abundant material, titania has gained attention for energy storage applications. This work studies titanate nano-structures created through hydrothermal treatment. Morphology, crystallinity, and electrochemical performance are analyzed as a function of treatment temperature and molarity. Samples are characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the electrochemical performance is determined by cycling coin-type half-cells

Investigating Ink Properties and 3D Printing Process Parameters for Manufacturing 3D Solid State Electrolytes

Building solid-state batteries with a three-dimensional (3D) structure represents a potential way to increase both their energy and power densities. 3D printing using inks is seen as a promising manufacturing method to create solid electrolytes for batteries with a complex architecture, but it is unclear how the properties of the ink and the 3D printing process parameters affect the resulting electrolyte. This project will investigate the material properties of electrolyte inks of varying compositions, as well as understand what 3D printing process parameters are necessary to yield high quality prints. To accomplish this, multiple printed electrolytes of varying geometries will be fabricated using different printing processes and different inks. Then, the printed electrolytes will be characterized to investigate the effect that this has on the crystal structure, shrinkage, and microstructure of the finished electrolyte

Nanoporous Niobium Oxide as an Anode for Na-ion Batteries

Solar, wind, and other renewable energy sources tend to be intermittent, and thus large-scale energy storage is needed to fully utilize them. While sodium-ion batteries currently fall short of the energy density of the leading lithium-ion technologies, they are a potentially cost-effective alternative, since sodium is more abundant but is chemically similar to lithium. Additionally, for stationary applications cost is a much larger driving factor than for mobile applications. However, improvements are needed to increase the stability and reliability of sodium-ion batteries before they become a legitimate option. Nanostructured metal oxides such as nanotube arrays are promising for use in anodes due to their high surface area and ability to withstand the volume changes that accompany repeated Na+ insertion/extraction during battery cycling. Niobium oxide is one such material, but research into its use in sodium-ion batteries is limited. Nanoporous niobium oxide films were synthesized via anodization of niobium foil, where the morphology was modified by changing the anodization voltage and the crystallinity was modified using heat treatments. The films were characterized with SEM and XRD, then cycled in half-cells with sodium foil counter electrodes to assess their electrochemical behavior

P2/P3 Heterostructured Layered Transition Metal Oxide Cathode Materials in Sodium-Ion Batteries

Lithium-ion batteries (LIBs) have been a popular option for many applications in electrical energy storage. However, concerns over the availability of lithium and cobalt, the two most common elements used in LIBs, have led to the renewed interest in more sustainable alternatives, especially in large-scale energy storage applications. Sodium-ion batteries (SIBs) have gained an interest as an alternative due to the large abundance of sodium and relatively low cost. In particular, layered transition metal oxides (LTMOs) have been the main focus of positive electrode materials research due to their high capacities, and high operating voltage. The P3-type Na0.5Ni0.25Mn0.75O2 material is a promising manganese-rich positive electrode for future SIBs due to its high working voltage and capacity. However, fast capacity fading due to the high voltage P3-O3 phase transition has been the bottleneck for commercialization of such materials. To combat this limitation, we attempted to synthesize a heterostructured P2-Na2/3MnO2-coated P3-Na0.5Ni0.25Mn0.75O2 cathode material. The created material exhibited an increased capacity of 119.3 mA h g-1 at 1C rate and improved cycling stability of 64.7% retention after 80 cycles at 1C. However, characterization techniques, including HR-TEM, SEM, and XRD, have not shown that the hypothesized layer has grown. Future research should be done into realizing the effect that our synthesis had upon the P3 material, and how to implement it towards the improvement of manganese-rich P3-type sodium LTMO cathode materials for future applications

Nanoporous Niobium Oxide Electrode for Sodium-Ion Batteries

The growing demand for renewable energy, like solar and wind, places an increasing need for large-scale energy storage systems. These systems are needed due to the intermittent nature of renewable energy sources. Li-ion batteries (LIB) have been selected to perform this task for its high energy storage. However, Li is relatively rare and has various obstacles to its production. Therefore, a more abundant and less expensive alternative is appealing. Sodium-ion batteries (SIB) has been considered a potential candidate for its abundance, low cost, and sustainability. Unfortunately, there are difficulties to overcome when implementing SIB. Sodium (Na) has a higher mass, larger ionic radius, and lower mobility compared to Lithium (Li). These properties cause a reduction in cycle stability, lower energy output, and increased stress/strain in the electrodes structure\u27s inability to support the difference between the two ions. Therefore, finding a new intercalation host that is capable of supporting the transfer of Na+ becomes paramount. This work explores the formation and use of niobium oxide as an anode material for SIBs. Anodization and temperature conditions were tuned to produce a variety of pore sizes with differing morphologies. Initial results indicate that the amorphous material formed at 30V performed at the highest capacity and is further explored herein