A Chemistry and Material Perspective On Lithium Redox Flow Batteries Towards High-Density Electrical Energy Storage

Electrical energy storage system such as secondary batteries is the principle power source for portable electronics, electric vehicles and stationary energy storage. As an emerging battery technology, Li-redox flow batteries inherit the advantageous features of modular design of conventional redox flow batteries and high voltage and energy efficiency of Li-ion batteries, showing great promise as efficient electrical energy storage system in transportation, commercial, and residential applications. The chemistry of lithium redox flow batteries with aqueous or non-aqueous electrolyte enables widened electrochemical potential window thus may provide much greater energy density and efficiency than conventional redox flow batteries based on proton chemistry. This Review summarizes the design rationale, fundamentals and characterization of Li-redox flow batteries from a chemistry and material perspective, with particular emphasis on the new chemistries and materials. The latest advances and associated challenges/opportunities are comprehensively discussed.Zhao, Yu, Yu Ding, Yutao Li, Lele Peng, Hye Ryung Byon, John B. Goodenough, and Guihua Yu. "A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage." Chemical Society Reviews 44, no. 22 (Nov., 2015): 7968-7996.Materials Science and Engineerin

Reducing time to discovery : materials and molecular modeling, imaging, informatics, and integration

This work was supported by the KAIST-funded Global Singularity Research Program for 2019 and 2020. J.C.A. acknowledges support from the National Science Foundation under Grant TRIPODS + X:RES-1839234 and the Nano/Human Interfaces Presidential Initiative. S.V.K.’s effort was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division and was performed at the Oak Ridge National Laboratory’s Center for Nanophase Materials Sciences (CNMS), a U.S. Department of Energy, Office of Science User Facility.Multiscale and multimodal imaging of material structures and properties provides solid ground on which materials theory and design can flourish. Recently, KAIST announced 10 flagship research fields, which include KAIST Materials Revolution: Materials and Molecular Modeling, Imaging, Informatics and Integration (M3I3). The M3I3 initiative aims to reduce the time for the discovery, design and development of materials based on elucidating multiscale processing-structure-property relationship and materials hierarchy, which are to be quantified and understood through a combination of machine learning and scientific insights. In this review, we begin by introducing recent progress on related initiatives around the globe, such as the Materials Genome Initiative (U.S.), Materials Informatics (U.S.), the Materials Project (U.S.), the Open Quantum Materials Database (U.S.), Materials Research by Information Integration Initiative (Japan), Novel Materials Discovery (E.U.), the NOMAD repository (E.U.), Materials Scientific Data Sharing Network (China), Vom Materials Zur Innovation (Germany), and Creative Materials Discovery (Korea), and discuss the role of multiscale materials and molecular imaging combined with machine learning in realizing the vision of M3I3. Specifically, microscopies using photons, electrons, and physical probes will be revisited with a focus on the multiscale structural hierarchy, as well as structure-property relationships. Additionally, data mining from the literature combined with machine learning will be shown to be more efficient in finding the future direction of materials structures with improved properties than the classical approach. Examples of materials for applications in energy and information will be reviewed and discussed. A case study on the development of a Ni-Co-Mn cathode materials illustrates M3I3's approach to creating libraries of multiscale structure-property-processing relationships. We end with a future outlook toward recent developments in the field of M3I3.Peer reviewe

Nanoporous NiO plates with a unique role for promoted oxidation of carbonate and carboxylate species in the Li-O2 battery

We report a novel catalytic reaction to promote oxidation of carbonate and carboxylate species using nanoporous nickel oxide (NiO) in the lithium-oxygen (Li-O2) battery. These nanoporous NiO catalysts in the shape of two-dimensional (2-D) hexagonal plates are incorporated on the carbon nanotube (CNT) electrode, which remarkably enhances oxidation efficiency of carbonate and carboxylate species as representative side products in Li-O2 electrochemistry and greatly improves the cycleability to more than 70 cycles. The oxidation reaction predominantly occurs at the nanoporous NiO, toward which the carbonate and carboxylate species may migrate for the complete decomposition. This result is notably distinguished from a NiO-free CNT electrode, where such a passivation layer becomes thicker and precludes electron transfer, thus inducing poor cyclability. © 2015 American Chemical Society154521sciescopu

Real-Time XRD Studies of Li–O₂ Electrochemical Reaction in Nonaqueous Lithium–Oxygen Battery

Understanding of electrochemical process in rechargeable Li–O₂ battery has suffered from lack of proper analytical tool, especially related to the identification of chemical species and number of electrons involved in the discharge/recharge process. Here we present a simple and straightforward analytical method for simultaneously attaining chemical and quantified information of Li₂O₂ (discharge product) and byproducts using in situ XRD measurement. By real-time monitoring of solid-state Li₂O₂ peak area, the accurate efficiency of Li₂O₂ formation and the number of electrons can be evaluated during full discharge. Furthermore, by observation of sequential area change of Li₂O₂ peak during recharge, we found nonlinearity of Li₂O₂ decomposition rate for the first time in ether-based electrolyte

High Energy Efficiency and Stability for Photoassisted Aqueous Lithium–Iodine Redox Batteries

We demonstrated photoassisted lithium–iodine (Li–I₂) redox cells integrated with a hematite photoelectrode that are applicable to energy storage systems (ESSs). The hematite photoelectrode presents low cost, light absorption in the visible light region, and inertness to aqueous electrolytes, which allow for stable production of photocurrent under illumination. In the aqueous Li–I₂ redox cells, the harnessing of photoenergy generates photocarriers that promote the I^– oxidation process without electrolysis of the aqueous solution. The energy efficiency for the photoassisted charge process is ∼95.4%, which is ∼20% higher than that in the absence of illumination at a current rate of 0.075 mA cm^–2. The hematite is profoundly stable in aqueous I^–/I₃^– catholyte and exhibits over 600 h of cycling without noticeable performance decay and photocorrosion. This achievement highlights photoinduced ESSs with improved energy efficiency

Nanoporous NiO Plates with a Unique Role for Promoted Oxidation of Carbonate and Carboxylate Species in the Li–O₂ Battery

We report a novel catalytic reaction to promote oxidation of carbonate and carboxylate species using nanoporous nickel oxide (NiO) in the lithium–oxygen (Li–O₂) battery. These nanoporous NiO catalysts in the shape of two-dimensional (2-D) hexagonal plates are incorporated on the carbon nanotube (CNT) electrode, which remarkably enhances oxidation efficiency of carbonate and carboxylate species as representative side products in Li–O₂ electrochemistry and greatly improves the cycleability to more than 70 cycles. The oxidation reaction predominantly occurs at the nanoporous NiO, toward which the carbonate and carboxylate species may migrate for the complete decomposition. This result is notably distinguished from a NiO-free CNT electrode, where such a passivation layer becomes thicker and precludes electron transfer, thus inducing poor cyclability

Naphthalene diimide as a two-electron anolyte for aqueous and neutral pH redox flow batteries

© The Royal Society of Chemistry 2020.Developing organic materials that show stable and highly reversible redox-activity is a key challenge for achieving cost-effective and sustainable aqueous redox flow batteries (RFBs) for practical energy storage applications. We report a water-soluble naphthalene diimide (NDI) derivative using carboxylate groups, which was tested and established as a new class of versatile anolytes capable of storing two electrons in a single molecule in aqueous and neutral pH RFBs. The potassium salt ofN,N′-bis(glycinyl)naphthalene diimide [K2-BNDI] showed reversible and stable two-electron reductions accompanied by ion- pairing. A prototype aqueous RFB consisting of [K2-BNDI] and 4-OH-TEMPO was constructed and showed excellent cyclability, high energy and voltage efficiencies. This study suggests a versatile way of designing new anolytes inspired by organic semiconductors that operate in a multi-electron redox mode11sci