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Cui, Yi

Publications and source records attributed to Cui, Yi.

At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Power system disturbance localization using recurrence quantification analysis and minimum-volume-enclosing ellipsoid

A method for determining a location of a disturbance in a power system is provided. The method includes receiving data from a plurality of sensors distributed across the power system; performing a recurrence quantification analysis on the received data to identify a predetermined number of sensors, from the plurality of sensors, that are closest to the disturbance; constructing a plurality of minimum-volume-enclosing ellipsoids based on and enclosing the data received from the identified sensors; extracting one or more parameters from the plurality of minimum-volume-enclosing ellipsoids; inputting the one or more parameters into a multivariate-random-forest regression algorithm to determine the location of the disturbance and a power mismatch corresponding to the disturbance; and presenting, on one or more display units, the determined location of the disturbance and the determined power mismatch.

Cui, Yi↗
DOE OSTI2019

A molten battery consisting of Li metal anode, AlCl3-LiCl cathode and solid electrolyte

High performance rechargeable batteries are crucially needed to address the demands of grid-scale stationary energy storage. High temperature battery systems, such as Na-S battery, Na-NiCl2 battery (ZEBRA battery) and liquid metal electrode (LME) battery, exhibit advantages like high power density and high cyclic stability, but also suffer from the high operating temperature. We recently invented new concept of molten lithium metal batteries, consisting of liquid lithium anodes, alloy (Sn, Bi, Pb) liquid cathodes and lithium ion conductor as solid electrolytes. Here we demonstrate a molten metal chloride battery that operates at a relatively low temperature of 210 °C. The battery has been designed to include molten (AlCl3-LiCl) cathode, solid electrolyte (garnet-type Li6.4La3Ta0.6Zr1.4O12 (LLZTO) ceramic tube) and molten lithium anode. The assembled AlCl3-LiCl||LLZTO||Li full cell has an average discharge voltage of 1.55 V and energy efficiency of 83% and has been successfully cycled for 100 cycles (800 h) without capacity fade. The theoretical specific energy of cell is 350 Wh/kg and the estimated cost is $11.6/kWh based on the weight of electrode materials. Considering the high performance, high safety, low operating temperature and low cost of raw materials, this novel type of molten-electrode battery system opens up new opportunities for stationary energy storage.

25 ENERGY STORAGE↗
DOE OSTI2019

Evolution of the Solid–Electrolyte Interphase on Carbonaceous Anodes Visualized by Atomic-Resolution Cryogenic Electron Microscopy

In this paper, the stability of modern lithium-ion batteries depends critically on an effective solid–electrolyte interphase (SEI), a passivation layer that forms on the carbonaceous negative electrode as a result of electrolyte reduction. However, a nanoscopic understanding of how the SEI evolves with battery aging remains limited due to the difficulty in characterizing the structural and chemical properties of this sensitive interphase. In this work, we image the SEI on carbon black negative electrodes using cryogenic transmission electron microscopy (cryo-TEM) and track its evolution during cycling. We find that a thin, primarily amorphous SEI nucleates on the first cycle, which further evolves into one of two distinct SEI morphologies upon further cycling: (1) a compact SEI, with a high concentration of inorganic components that effectively passivates the negative electrode; and (2) an extended SEI spanning hundreds of nanometers. This extended SEI grows on particles that lack a compact SEI and consists primarily of alkyl carbonates. The diversity in observed SEI morphologies suggests that SEI growth is a highly heterogeneous process. The simultaneous emergence of these distinct SEI morphologies highlights the necessity of effective passivation by the SEI, as large-scale extended SEI growths negatively impact lithium-ion transport, contribute to capacity loss, and may accelerate battery failure.

25 ENERGY STORAGE↗
DOE OSTI2019

Charge-Free Mixing Entropy Battery Enabled by Low-Cost Electrode Materials

Salinity gradients are a vast and untapped energy resource. For every cubic meter of freshwater that mixes with seawater, approximately 0.65 kW h of theoretically recoverable energy is lost. For coastal wastewater treatment plants that discharge to the ocean, this energy, if recovered, could power the plant. The mixing entropy battery (MEB) uses battery electrodes to convert salinity gradient energy into electricity in a four-step process: (1) freshwater exchange; (2) charging in freshwater; (3) seawater exchange; and (4) discharging in seawater. Previously, we demonstrated a proof of concept, but with electrode materials that required an energy investment during the charging step. Here, we introduce a charge-free MEB with low-cost electrodes: Prussian Blue (PB) and polypyrrole (PPy). Importantly, this MEB requires no energy investment, and the electrode materials are stable with repeated cycling. The MEB equipped with PB and PPy achieved high voltage ratios (actual voltages obtained divided by the theoretical voltages) of 89.5% in wastewater effluent and 97.6% in seawater, with over 93% capacity retention after 50 cycles of operation and 97–99% over 150 cycles with a polyvinyl alcohol/sulfosuccinic acid (PVA/SSA) coating on the PB electrode.

25 ENERGY STORAGE↗
DOE OSTI2019

Improving cyclability of Li metal batteries at elevated temperatures and its origin revealed by cryo-electron microscopy

Operations of lithium-ion batteries have long been limited to a narrow temperature range close to room temperature. At elevated temperatures, cycling degradation speeds up due to enhanced side reactions, especially when high-reactivity lithium metal is used as the anode. In this work, we demonstrate enhanced performance in lithium metal batteries operated at elevated temperatures. In an ether-based electrolyte at 60 °C, an average Coulombic efficiency of 99.3% is obtained and more than 300 stable cycles are realized, but, at 20 °C, the Coulombic efficiency drops dramatically within 75 cycles, corresponding to an average Coulombic efficiency of 90.2%. Cryo-electron microscopy reveals a drastically different solid electrolyte interface nanostructure emerging at 60 °C, which maintains mechanical stability, inhibits continuous side reactions and guarantees good cycling stability and low electrochemical impedance. Additionally, larger lithium particles grown at the elevated temperature reduce the electrolyte/electrode interfacial area, which decreases the per-cycle lithium loss and enables higher Coulombic efficiencies.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Hexacyanometallates as highly conducting solid electrolytes for batteries

Described here is a solid-state lithium-ion battery, comprising a cathode, an anode, and a solid-state electrolyte disposed between the cathode and the anode, wherein the electrolyte comprises a hexacyanometallate represented by AxPy[R(CN)6-wLw]z, wherein: A is at least one alkali metal cation, P is at least one transition metal cation, at least one post-transition metal cation, and/or at least one alkaline earth metal cation, R is at least one transition metal cation, L is an anion, x, y, and z are related based on electrical neutrality, x>0, y>0, z>0, and 0≤w≤6.

25 ENERGY STORAGE↗
DOE OSTI2019

Remediation of heavy metal contaminated soil by asymmetrical alternating current electrochemistry

Soil contamination by heavy metals constitutes an important environmental problem, whereas field applicability of existing remediation technologies has encountered numerous obstacles, such as long operation time, high chemical cost, large energy consumption, secondary pollution, and soil degradation. Here we report the design and demonstration of a remediation method based on a concept of asymmetrical alternating current electrochemistry that achieves high degrees of contaminant removal for different heavy metals (copper, lead, cadmium) at different initial concentrations (from 100 to 10,000 ppm), all reaching corresponding regulation levels for residential scenario after rational treatment time (from 30 min to 6 h). No excessive nutrient loss in treated soil is observed and no secondary toxic product is produced. Long-term experiment and plant assay show the high sustainability of the method and its feasibility for agricultural use.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Challenges and opportunities towards fast-charging battery materials

Extreme fast charging, with a goal of 15 minutes recharge time, is poised to accelerate mass market adoption of electric vehicles, curb greenhouse gas emissions and, in turn, provide nations with greater energy security. However, the realization of such a goal requires research and development across multiple levels, with battery technology being a key technical barrier. The present-day high-energy lithium-ion batteries with graphite anodes and transition metal oxide cathodes in liquid electrolytes are unable to achieve the fast-charging goal without negatively affecting electrochemical performance and safety. Here we discuss the challenges and future research directions towards fast charging at the level of battery materials from mass transport, charge transfer and thermal management perspectives. Additionally, we highlight advanced characterization techniques to fundamentally understand the failure mechanisms of batteries during fast charging, which in turn would inform more rational battery designs.

25 ENERGY STORAGE↗
DOE OSTI2019

Ionic-Liquid-Gating Induced Protonation and Superconductivity in FeSe, FeSe 0.93 S 0.07 , ZrNCl, 1 T -TaS 2 and Bi 2 Se 3 *

We report protonation in several compounds by an ionic-liquid-gating method, under optimized gating conditions. This leads to single superconducting phases for several compounds. Non-volatility of protons allows post-gating magnetization and transport measurements. The superconducting transition temperature T c is enhanced to 43.5 K for FeSe 0.93 S 0.07 , and 41 K for FeSe after protonation. Superconducting transitions with T c ~ 15 K for ZrNCl, ~7.2 K for 1T-TaS 2 , and ~3.8 K for Bi 2 Se 3 are induced after protonation. Electric transport in protonated FeSe 0.93 S 0.07 confirms high-temperature superconductivity. Our 1 H nuclear magnetic resonance (NMR) measurements on protonated FeSe 1- x S x reveal enhanced spin-lattice relaxation rate 1/ 1 T 1 with increasing x , which is consistent with the LDA calculations that H + is located in the interstitial sites close to the anions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Temperature-Dependent Nucleation and Growth of Dendrite-Free Lithium Metal Anodes

It is essential to develop a facile and effective method to enhance the electrochemical performance of lithium metal anodes for building high–energy–density Li–metal based batteries. Herein, we explored the temperature–dependent Li nucleation and growth behavior and constructed a dendrite–free Li metal anode by elevating temperature from room temperature (20 °C) to 60 °C. A series of ex situ and in situ microscopy investigations demonstrate that increasing Li deposition temperature results in large nuclei size, low nucleation density, and compact growth of Li metal. We reveal that the enhanced lithiophilicity and the increased Li–ion diffusion coefficient in aprotic electrolytes at high temperature are essential factors contributing to the dendrite–free Li growth behavior. In conclusion, as anodes in both half cells and full cells, the compact deposited Li with minimized specific surface area delivered high Coulombic efficiencies and long cycling stability at 60 °C.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Ultrathin, flexible, solid polymer composite electrolyte enabled with aligned nanoporous host for lithium batteries

The urgent need for safer batteries is leading research to all-solid-state lithium-based cells. To achieve energy density comparable to liquid electrolyte-based cells, ultrathin and lightweight solid electrolytes with high ionic conductivity are desired. However, solid electrolytes with comparable thicknesses to commercial polymer electrolyte separators (~10 μm) used in liquid electrolytes remain challenging to make because of the increased risk of short-circuiting the battery. In this work, we report on a polymer–polymer solid-state electrolyte design, demonstrated with an 8.6-μm-thick nanoporous polyimide (PI) film filled with polyethylene oxide/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) that can be used as a safe solid polymer electrolyte. The PI film is nonflammable and mechanically strong, preventing batteries from short-circuiting even after more than 1,000 h of cycling, and the vertical channels enhance the ionic conductivity (2.3 × 10 -4 S cm -1 at 30 °C) of the infused polymer electrolyte. Lastly, all-solid-state lithium-ion batteries fabricated with PI/PEO/LiTFSI solid electrolyte show good cycling performance (200 cycles at C/2 rate) at 60 °C and withstand abuse tests such as bending, cutting and nail penetration.

25 ENERGY STORAGE↗
DOE OSTI2019

Direct/Alternating Current Electrochemical Method for Removing and Recovering Heavy Metal from Water Using Graphene Oxide Electrode

Treatment of heavy-metal pollution in both point-of-use water and industrial wastewater is critical in protecting human health and the environment. Current methods for heavy-metal treatment in both sources have limitations. For point-of-use water, current methods usually suffer from limited capacity and difficulties in spontaneously removing multiple heavy metals. For industrial wastewater, current methods greatly reduce the value of heavy metal by precipitating them as sludge which requires further treatment. Here we developed an electrochemical method that can treat both low-concentration and high-concentration heavy-metal pollution using either direct current (DC) or alternating current (AC) electrodeposition with graphene-oxide-modified carbon felt electrode (CF-GO). The graphene oxide provides a high density of surface functional groups to assist the electrodeposition. The electrodeposition method showed 2 orders of magnitude higher capacity (>29 g heavy metal for 1 g of graphene oxide) compared with traditional adsorption methods. For low levels of heavy-metal pollution in point-of-use water, DC electrodeposition with a CF-GO electrode can reduce single heavy-metal ion pollution (Cu, Cd, and Pb) as well as multiple ion mixtures to below safe water drinking levels. This method can tolerate a much wider range of heavy-metal pollution in point-of-use water than traditional adsorption methods. For high-level pollution in industrial wastewater, AC electrodeposition can recover >99.9% heavy-metal ions. Finally, by tuning the AC frequency and voltage, the electrodeposition method can further selectively recover Cu, Cd, and Pb separately, which adds values to the heavy-metal removal process.

36 MATERIALS SCIENCE↗