Carbon Enhanced Lead Acid Batteries
This program focuses on developing a fundamental physical, chemical, and electrochemical understanding of the mechanism of the enhanced performance of carbon-enhanced valve-regulated lead-acid battery (VRLA) batteries. Their electrochemical performance will be characterized as well as the physical and chemical changes that take place over the batteries’ lifetime. A mechanistic understanding of the manner in which carbon enhances VRLA battery performance under high-rate, partial state-of-charge operation when added to the negative active material will be developed.
Sodium Based Batteries for Large Scale Storage
In a transformational move away from lithium-based battery systems, the project team will initiate development of a family of new, high-energy density sodium-based battery chemistries. These include sodium-ion, sodium-halogen, low-temperature sodium-sulfur, sodium-water, sodium-air and others. The opportunity to develop a family of batteries rather than just single battery chemistry is engendered by the recent development of a solid, sodium-ion conductor that exhibits: 1) long-term stability when in direct contact with molten sodium; 2) long-term stability against a variety of cathode chemistries; 3) a high degree of permselectivity; and 4) high sodium-ion conductivity. Successful development of sodium-based battery systems will free the United States from further reliance on foreign resources since the United States is a net exporter of sodium in several forms (e.g., as caustic) and has significant reserves of sodium, unlike the case of lithium which is used in lithium-ion batteries. Furthermore, while large-scale commodity use is subject to market forces, the absolute magnitude of sodium reserves are sufficiently large that battery target costs of < 100 $/kWh are feasible.
Thermoelectrochemical Energy Storage
The voltage of a battery includes a contribution from a temperature dependent term. For some battery chemistries, this thermal contribution can be significant, and the battery voltage can be dramatically altered merely by changing the temperature profile of the cell. It should be possible to couple this behavior with the charge and discharge portions of the battery cycle to lower the electrical requirement on the charge cycle and maximize the amount of electrical energy returned on discharge portion of the cycle. In this way, the thermal energy in the form of low-grade waste heat can be captured and returned as high-grade electrical energy. For this project, a flow battery is envisioned in which the reactants are pumped from/to the storage tanks in different thermal environments, and then coupling these thermal environments to the charge or discharge portion of the battery cycle. While the total energy input to the system is fixed, the electrical efficiency of the battery system will be increased due the fact that a portion of the energy provided is thermal energy.