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At least 955 records · Page 53

Minimizing Polysulfide Shuttle Effect in Lithium-Ion Sulfur Batteries by Anode Surface Passivation

Lithium-ion sulfur batteries use non-metal materials as the anode to address safety concerns associated with lithium metal anode. However, polysulfide shuttle reactions still occur on the non-metal anode (such as graphite and Si), and result in limited battery efficiency. In this work, we used Al2O3 layers coated by atomic layer deposition (ALD) technique to suppress the shuttle reactions. With the optimal thickness of 2 nm Al2O3 coated on graphite anode, the Coulombic efficiency of the sulfur cathode was improved from 84% to 96% in the first cycle, and from 94% to 97% in the subsequent cycles. As a result, the discharge capacity of the sulfur cathode was increased to 550 mAh g-1 in the 100th cycle, as compared with 440 mAh g-1 when the pristine graphite anode was used. The Al2O3 passivation layer minimizes the formation of insoluble polysulfide (Li2S2, Li2S) on the surface of graphite anode and improves the efficiency and capacity retention of the graphite-sulfur batteries. The surface passivation strategy could also be used in other Li sulfur battery systems (with Li, Si, and Sn anodes), to minimize side reactions and enable high-performance and safe sulfur batteries.

Liu, Jian↗

Current collection by high voltage anodes in near ionospheric conditions

The authors experimentally identified three distinct regimes with large differences in current collection in the presence of neutrals and weak magnetic fields. In magnetic field/anode voltage space the three regions are separated by very sharp transition boundaries. The authors performed a series of laboratory experiments to study the dependence of the region boundaries on several parameters, such as the ambient neutral density, plasma density, magnetic field strength, applied anode voltage, voltage pulsewidth, chamber material, chamber size and anode radius. The three observed regimes are: classical magnetic field limited collection; stable medium current toroidal discharge; and large scale, high current space glow discharge. There is as much as several orders of magnitude of difference in the amount of collected current upon any boundary crossing, particularly if one enters the space glow regime. They measured some of the properties of the plasma generated by the breakdown that is present in regimes II and III in the vicinity of the anode including the sheath modified electrostatic potential, I-V characteristics at high voltage as well as the local plasma density.

Antoniades, John A.↗

High power, extended temperature range-capable, highly abuse overcharge and discharge tolerant rechargeable battery cell and pack

Provided are electrochemical secondary cells that exhibit excellent abuse tolerance, deep discharge and overcharge conditions including at extreme temperatures and remain robust and possess excellent performance. Cells as provided herein include: a cathode a polycrystalline cathode electrochemically active material including the formula Li1+xMO2+y, wherein −0.9≤x≤0.3, −0.3≤y≤0.3, and wherein M includes Ni at 80 atomic percent or higher relative to total M, the cathode electrochemically active material comprising a non-uniform distribution of Co; an anode including an anode electrochemically active material of the formula Li4+aTi5O12+b wherein −0.3≤a≤3.3, −0.3≤b≤0.3; and wherein the anode and the cathode each independently include a current collector substrate comprising aluminium.

Sahin, Kenan↗

Hybrid anodes for energy storage devices

Energy storage devices having hybrid anodes can address at least the problems of active material consumption and anode passivation that can be characteristic of traditional batteries. The energy storage devices each have a cathode separated from the hybrid anode by a separator. The hybrid anode includes a carbon electrode connected to a metal electrode, thereby resulting in an equipotential between the carbon and metal electrodes.

25 ENERGY STORAGE↗

High Throughput Laser Processing for Enhanced Battery Performance and Manufacturing

For widespread adoption of electric vehicles, lithium-ion batteries (LiBs) need to achieve energy densities of >275 Wh/kg, cell costs less than $100/kWh, and charge to more than 80% capacity within 15 minutes. Recently, it has been shown that introducing a secondary pore network in thick battery electrodes enables higher extracted capacity without a severe reduction in charge/discharge rate performance. Secondary pore networks consisting of ordered arrays of microstructures reduce tortuosity of Li+-ion transport deep into the thick electrodes, diminishing detrimental concentration gradients within the cell. Ultrafast (femtosecond)-pulsed laser ablation is a promising method to introduce such micro pores or channels in thick battery electrodes as it allows for precise control of pattern geometries, results in minimal damage to the electrode, and can be introduced into existing roll-to-roll electrode manufacturing lines. We have explored laser patterning to create secondary pore networks in a variety of battery electrode materials for both anode and cathode applications and characterized the laser-material interaction parameters. In addition, advanced materials characterization techniques (SEM-EDS, XRD) were used to explore whether ultrafast laser ablation affects the remaining electrode materials' morphology and structure. Furthermore, we have translated lab-scale laser ablation to high-throughput roll-to-roll processing at industrially relevant scales. Finally, we worked with Argonne National Laboratory, developers of the battery cost-analysis package BatPac, to estimate the additional manufacturing costs (CapEx and OpEx) for incorporation of laser-ablation processing to current battery electrode manufacturing. We estimate that ultrafast laser processing will add only -$1kWh, which for considerable improvements in cell performance, creates a compelling case for industry adoption.

battery↗

Sustainable Potassium-Ion Battery Anodes Derived from Waste-Tire Rubber

The recycling of waste-tire rubber is of critical importance since the discarded tires pose serious environmental and health hazards to our society. Here, we report a new application for hard-carbon materials derived from waste-tires as anodes in potassium-ion batteries. The sustainable tire-derived carbons show good reversible potassium insertion at relatively high rates. Long-term stability tests exhibit capacities of 155 and 141 mAh g –1 for carbon pyrolyzed at 1100°C and 1600°C, respectively, after 200 cycles at current rate of C/2. As a result, this study provides an alternative solution for inexpensive and environmental benign potassium-ion battery anode materials.

25 ENERGY STORAGE↗

Coal as Value-Added for Lithium Battery Anodes (Final Report)

Graphite is a basic material used for energy storage in lithium-ion (Li-ion) batteries. More than 70% of worldwide graphite production and nearly 50% of the annual graphite supply for the United States comes from China. Potential economic and national security concerns exist because Li-ion batteries are used not only for the fast-growing electrical vehicle market (15.6% compound annual growth rate [CAGR] from 2018 to 2028 in North America), but also for defense applications including unmanned aerial and ground vehicles. Development of an alternative formulation for Li-ion batteries is key. Building upon previous research confirming the ability of silicon alloys to improve the energy density of anodes, Semplastics developed a novel material based on our X-MAT® polymer-derived ceramic (PDC) technology. The X-MAT anode material is a composite of chemically tailored silicon oxycarbide (SiOC) and domestically sourced coal powder, designed to be a drop-in replacement for graphite within Li-ion battery anodes. Preliminary tests of this material showed more than twice the reversible capacity of graphite anodes (1,000 mAh/g vs. 372 mAh/g), with excellent stability and capacity retention, almost 100% coulombic efficiency, low voltage potential, and low thermal expansion. At full adoption in 2024, we expect the coal utilization to reach 27,300 tons. Through this project, Semplastics proposed to complete development and begin commercialization of this material. The objective was to determine the best formulation for technical performance and economic viability. At the end of the project, the X-MAT anode material is ready for implementation into existing battery manufacturing processes and can have a significant impact on the utilization of coal, with positive effects for the mining sector and the mitigation of carbon dioxide (CO 2 ) emissions.

01 COAL, LIGNITE, AND PEAT↗

Electrochemically Stable Coating Materials for Li, Na, and Mg Metal Anodes in Durable High Energy Batteries

Anodes made of Li, Na, or Mg metal present a rare opportunity to double the energy density of rechargeable batteries. However, these metals are highly reactive with many electrolytes and yield electronically conductive phases that allow continued electrochemical reduction of the electrolyte. This reactivity degrades cell performance over time and poses a safety risk. Surface coatings on metal anodes can limit reactivity with electrolytes and improve durability. In this paper, we screen the Open Quantum Materials Database (OQMD) to identify coatings that exhibit chemical equilibrium with the anode metals and are electronic insulators. We rank the coatings according to their electronic bandgap. We identify 92 coatings for Li anodes, 118 for Na anodes, and 97 for Mg anodes. Only two compounds that are commonly studied as Li solid electrolytes pass our screens: Li 3 N and Li 7 La 3 Hf 2 O 12 . Many of the coatings that we identify are new to the battery literature. We suggest further study of these coatings to validate their performance in cells.

25 ENERGY STORAGE↗

Template-Free Synthesis of Hollow-Structured Co 3 O 4 Nanoparticles as High-Performance Anodes for Lithium-Ion Batteries

We have developed a template-free procedure to synthesize Co 3 O 4 hollow-structured nanoparticles on a Vulcan XC-72 carbon support. The material was synthesized via an impregnation–reduction method followed by air oxidation. In contrast to spherical particles, the hollow-structured Co 3 O 4 nanoparticles exhibited excellent lithium storage capacity, rate capability, and cycling stability when used as the anode material in lithium-ion batteries. Electrochemical testing showed that the hollow-structured Co 3 O 4 particles delivered a stable reversible capacity of about 880 mAh/g (near the theoretical capacity of 890 mAh/g) at a current density of 50 mA/g after 50 cycles. Lastly, the superior electrochemical performance is attributed to its unique hollow structure, which combines nano- and microscale properties that facilitate electron transfer and enhance structural robustness.

25 ENERGY STORAGE↗

Nanoscale perspective: Materials designs and understandings in lithium metal anodes

Li metal chemistry is a promising alternative with a much higher energy density than that of state-of-the-art Li-ion counterparts. However, significant challenges including safety issues and poor cyclability have severely impeded Li metal technology from becoming viable. In recent years, nanotechnologies have become increasingly important in materials design and fabrication for Li metal anodes, contributing to major progress in the field. In this review, we first introduce the main achievements in Li metal battery systems fulfilled by nanotechnologies, particularly regarding Li metal anode design and protection, ultrastrong separator engineering, safety monitoring, and smart functions. Next, we introduce recent studies on nanoscale Li nucleation/deposition. Lastly, we discuss possible future research directions. We hope this review delivers an overall picture of the role of nanoscale approaches in the recent progress of Li metal battery technology and inspires more research in the future.

36 MATERIALS SCIENCE↗

One-pot synthesis of a metal–organic framework as an anode for Li-ion batteries with improved capacity and cycling stability

Metal–organic framework is a kind of novel electrode materials for lithium ion batteries. Here, a 3D metal–organic framework Co{sub 2}(OH){sub 2}BDC (BDC=1,4-benzenedicarboxylate) was synthesized for the first time by the reaction of Co{sup 2+} with a bio-inspired renewable organic ligand 1,4-benzenedicarboxylic acid through a solvothermal method. As an anode material for lithium ion batteries, this material exhibited an excellent cyclic stability as well as a large reversible capacity of ca. 650 mA h g{sup −1} at a current density of 50 mA g{sup −1} after 100 cycles within the voltage range of 0.02–3.0 V, higher than that of other BDC based anode. - Graphical abstract: The PXRD pattern and the cycleability curves (inset) of Co{sub 2}(OH){sub 2}BDC. Display Omitted - Highlights: • Co{sub 2}(OH){sub 2}BDC was synthesized through a one pot solvothermal process. • The solvent had a great effect on the purity of this material. • This material was used as anode material for lithium ion batteries for the first time. • Co{sub 2}(OH){sub 2}BDC showed improved capacity and cycling stability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Laser pumping of thyristors for fast high current rise-times

An optically triggered semiconductor switch includes an anode metallization layer; a cathode metallization layer; a semiconductor between the anode metallization layer and the cathode metallization layer and a photon source. The semiconductor includes at least four layers of alternating doping in the form P-N-P-N, in which an outer layer adjacent to the anode metallization layer forms an anode and an outer layer adjacent the cathode metallization layer forms a cathode and in which the anode metallization layer has a window pattern of optically transparent material exposing the anode layer to light. The photon source emits light having a wavelength, with the light from the photon source being configured to match the window pattern of the anode metallization layer.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Using X-ray Microscopy To Understand How Nanoporous Materials Can Be Used To Reduce the Large Volume Change in Alloy Anodes

Tin metal is an attractive negative electrode material to replace graphite in Li-ion batteries due to its high energy density. However, tin undergoes a large volume change upon alloying with Li, which pulverizes the particles, and ultimately leads to short cycling lifetimes. Nevertheless, nanoporous materials have been shown to extend battery life well past what is observed in nonporous material. Despite the exciting potential of porous alloying anodes to significantly increase the energy density in Li-ion batteries, the fundamental physics of how nanoscale architectures accommodate the electrochemically induced volume changes are poorly understood. Here, operando transmission X-ray microscopy has been used to develop an understanding of the mechanisms that govern the enhanced cycling stability in nanoporous tin. We found that in comparison to dense tin, nanoporous tin undergoes a 6-fold smaller areal expansion after lithiation, as a result of the internal porosity and unique nanoscale architecture. The expansion is also more gradual in nanoporous tin compared to the dense material. The nanoscale resolution of the microscope used in this study is ~30 nm, which allowed us to directly observe the pore structure during lithiation and delithiation. We found that nanoporous tin remains porous during the first insertion and desinsertion cycle. This observation is key, as fully closed pores could lead to mechanical instability, electrolyte inaccessibility, and short lifetimes. Here, while tin was chosen for this study because of its high X-ray contrast, the results of this work should be general to other alloy-type systems, such as Si, that also suffer from volume change based cycling degradation.

36 MATERIALS SCIENCE↗

Experimental breakdown of selected anodized aluminum samples in dilute plasmas

Anodized aluminum samples representative of Space Station Freedom structural material were tested for electrical breakdown under space plasma conditions. In space, this potential arises across the insulating anodized coating when the spacecraft structure is driven to a negative bias relative to the external plasma potential due to plasma-surface interaction phenomena. For anodized materials used in the tests, it was found that breakdown voltage varied from 100 to 2000 volts depending on the sample. The current in the arcs depended on the sample, the capacitor, and the voltage. The level of the arc currents varied from 60 to 1000 amperes. The plasma number density varied from 3 x 10 exp 6 to 10 exp 3 ions per cc. The time between arcs increased as the number density was lowered. Corona testing of anodized samples revealed that samples with higher corona inception voltage had higher arcing inception voltages. From this it is concluded that corona testing may provide a method of screening the samples.

Grier, Norman T.↗

An Accelerated Testing and Analysis Framework for Qualification of Battery Materials

The continuously growing demand for batteries used within automotive, aviation, and grid applications has exacerbated the need to supplement critical battery material feedstocks, such as those for anode and cathode active materials. New or supplementary material sources, however, universally comprise unique material properties that can significantly affect the lifetime and performance of resultant batteries. As such, the influence of composition, microstructure, and morphology on electrochemical performance should be characterized quickly and accurately to accelerate commercialization of new material sources. This work introduces a tiered framework to quickly assess new material viability and understand the influence of physicochemical properties on battery performance. The Tier 1 testing described here is rapid and lower-effort to quickly recognize materials with fundamental flaws and potentially disqualify them. Later testing would require more time and effort but provide higher fidelity information with a goal of validating materials for specific applications. A case study examining various commercial sources of LiFePO4 (LFP) is presented, using Tier 1 of the protocol to identify rapid electrochemical and physicochemical signals that correlate with performance and to provide early go/no-go decisions on LFP materials without the need for long-term cycling data.

25 - ENERGY STORAGE↗