Radical New Energy Storage Solutions
Dr. Arun Majumdar is the Jay Precourt Provostial Chair Professor at Stanford University, a faculty member of the Departments of Mechanical Engineering and Materials Science and Engineering (by courtesy) and Senior Fellow and former Director of the Precourt Institute for Energy. He is also a faculty in Department of Photon Science at SLAC.
Flow batteries are a compelling grid-scale energy storage technology because the stored energy is decoupled from the system power. Aqueous redox flow batteries (RFBs), however, are limited by low open-circuit voltages (OCVs). Replacing the aqueous negative electrolyte (negolyte) with liquid alkali metals—of which Na-K, a room-temperature liquid metal alloy, is attractive—would increase the OCV considerably. However, a suitable solid electrolyte has not been reported for Na-K.
Interfaces between alkali metal solid state electrolytes and aqueous solutions are often unstable. In particular, the use of β/β″ alumina superionic conductors is generally limited to conditions absent of liquid water due to their well-known sensitivity to water vapor. However, the degradation mechanism upon exposure to aqueous solutions is not well understood. Using impedance spectroscopy, infrared spectroscopy, and chemical analysis, we studied the mechanism of ionic impedance rise for K+-ion-conducting, polycrystalline K-β″ alumina membranes in room temperature aqueous solutions.
We are engaged in theory and modeling of materials at the atomic scale. Our recent work has two primary directions:
1. Monolayer and few layer materials (i.e. graphene, MoS2) for electronics, NEMS, and energy applications.
2. Materials at conditions of high temperature, electromagnetic fields, and pressures, including dynamic or shock compression.
We present a new type of large-scale computational screening approach for identifying promising candidate materials for solid state electrolytes for lithium ion batteries that is capable of screening all known lithium containing solids. To be useful for batteries, high performance solid state electrolyte materials must satisfy many requirements at once, an optimization that is difficult to perform experimentally or with computationally expensive ab initio techniques.
Batteries including lithium-ion, lead–acid, redox-flow and liquid-metal batteries show promise for grid-scale storage, but they are still far from meeting the grid's storage needs such as low cost, long cycle life, reliable safety and reasonable energy density for cost and footprint reduction. Here, we report a rechargeable manganese–hydrogen battery, where the cathode is cycled between soluble Mn2+ and solid MnO2 with a two-electron reaction, and the anode is cycled between H2gas and H2O through well-known catalytic reactions of hydrogen evolution and oxidation.
Electrolyte engineering is critical for developing Li metal batteries. While recent works improved Li metal cyclability, a methodology for rational electrolyte design remains lacking. Herein, we propose a design strategy for electrolytes that enable anode-free Li metal batteries with single-solvent single-salt formations at standard concentrations. Rational incorporation of –CF2– units yields fluorinated 1,4-dimethoxylbutane as the electrolyte solvent.
Large-scale energy storage is of significance to the integration of renewable energy into electric grid. Despite the dominance of pumped hydroelectricity in the market of grid energy storage, it is limited by the suitable site selection and footprint impact. Rechargeable batteries show increasing interests in the large-scale energy storage; however, the challenging requirement of low-cost materials with long cycle and calendar life restricts most battery chemistries for use in the grid storage.
Cui studies fundamentals and applications of nanomaterials and develops tools for their understanding. Research Interests: nanotechnology, batteries, electrocatalysis, wearables, 2D materials, environmental technology (water, air, soil), cryogenic electron microscopy.
The availability of low-cost but intermittent renewable electricity (e.g., derived from solar and wind) underscores the grand challenge to store and dispatch energy so that it is available when and where it is needed. Redox-active materials promise the efficient transformation between electrical, chemical, and thermal energy, and are at the heart of carbon-neutral energy cycles. Understanding design rules that govern materials chemistry and architecture holds the key towards rationally optimizing technologies such as batteries, fuel cells, electrolyzers, and novel thermodynamic cycles.