Storage

Oak Ridge National Laboratory (ORNL) will develop glassy Li-ion conductors that are electrochemically and mechanically stable against lithium metal and can be integrated into full battery cells. Metallic lithium anodes could significantly improve the energy density of batteries versus today’s state-of-the-art lithium ion cells. ORNL has chosen glass as a solid barrier because the lack of grain boundaries in glass mitigates the growth of branchlike metal fibers called dendrites, which short-circuit battery cells.

United Technologies Research Center (UTRC) will develop a proof-of-concept for an innovative new vehicle energy-storage system. The UTRC team is leveraging experience from a previous ARPA-E project focused on grid-scale energy storage, the GRIDS: Breakthrough Flow Battery Cell Stack project, to develop a high-performance redox-air flow cell (RFC) system for EVs. A flow battery is a cross between a traditional battery and a fuel cell. Flow batteries store their energy in external tanks instead of inside the cell itself.

Princeton University is developing a non-invasive, low-cost, ultrasonic diagnostic system to determine battery state-of-health and state-of-charge, and to monitor internal battery defects. This system links the propagation of sound waves through a battery to the material properties of components within the battery. As a battery is cycled, the density and mechanical properties of its electrodes change; as the battery ages, it experiences progressive formation and degradation of critical surface layers, mechanical degradation of electrodes, and consumption of electrolyte.

The University of Tennessee (UT) will develop a reversible Oxygen Reduction Reaction (ORR) catalyst that can be used both as a peroxide-producing electrolyzer and in reversible air batteries. The ORR catalyst development seeks to significantly improve peroxide electrolysis efficiency and achieve high charge and discharge rates in air-breathing batteries. In conjunction with the new catalyst, an anion exchange membrane (AEM) will be used to further increase the electrolyzer efficiency and reduce peroxide production costs.

The University of Maryland (UMD) will develop a new type of current collector using a film that is composed of functionalized few-walled carbon nanotubes (FWNTs) and polymers. The team seeks to develop a thin, low-cost current collector that displays high conductivity, excellent mechanical strength, flexibility, and manufacturing scalability. Carbon nanotubes have high conductivity, but in their pure state lack the needed mechanical strength. The FWNT concept will "functionalize" or bolster the outer walls by integrating polymers to increase the mechanical strength.

Massachusetts Institute of Technology (MIT) is developing a low-cost, compact, high-capacity, advanced thermo-adsorptive battery (ATB) for effective climate control of EVs. The ATB provides both heating and cooling by taking advantage of the materials' ability to adsorb a significant amount of water. This efficient battery system design could offer up as much as a 30% increase in driving range compared to current EV climate control technology. The ATB provides high-capacity thermal storage with little-to-no electrical power consumption.

Abengoa Solar is developing a high-efficiency solar-electric conversion tower to enable low-cost, fully dispatchable solar energy generation. Abengoa's conversion tower utilizes new system architecture and a two-phase thermal energy storage media with an efficient supercritical carbon dioxide (CO2) power cycle. The company is using a high-temperature heat-transfer fluid with a phase change in between its hot and cold operating temperature. The fluid serves as a heat storage material and is cheaper and more efficient than conventional heat-storage materials, like molten salt.

The University of South Florida (USF) is developing low-cost, high-temperature phase-change materials (PCMs) for use in thermal energy storage systems. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Most PCMs do not conduct heat very well.

Massachusetts Institute of Technology (MIT) is developing efficient heat storage materials for use in solar and nuclear power plants. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun's not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours.

Pacific Northwest National Laboratory (PNNL) is developing a thermal energy storage system based on a Reversible Metal Hydride Thermochemical (RMHT) system, which uses metal hydride as a heat storage material. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours.