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At least 487 records · Page 27

Durian-Inspired Design of Bismuth–Antimony Alloy Arrays for Robust Sodium Storage

Sodium-ion batteries have attracted widespread attention for cost-effective and large-scale electric energy storage. However, their practical deployment has been largely retarded by the lack of choice of efficient anode materials featuring large capacity and electrochemical stability and robustness. Herein, we report a durian-inspired design and template-free fabrication of a robust sodium anode based on triangular pyramid arrays of Bi 0.75 Sb 0.25 alloy electrodeposited on Cu substrates. The Bi 0.75 Sb 0.25 arrays exhibit an appreciable electrochemical robustness for sodium storage, sustaining a reversible capability 335 mAh g –1 at a high rate of 2.5 A g –1 and 87% of the initial capacity over 2000 cycles. We further demonstrate the applicability of the Bi 0.75 Sb 0.25 array anode in sodium full cells by pairing it with a Na 3 V 2 (PO 4 ) 3 /C cathode. This full cell achieves a high specific energy of 203 Wh kg –1 (based on both active electrodes). Such an enhanced performance is attributed to the thorny-durian-like architecture and bimetallic alloy composition. In conclusion, the pyramid tip induces ion enrichment for rapid charge-transfer reaction, while the alloy design reduces the electrode volume swelling for stable Na cycling.

25 ENERGY STORAGE↗

Attachment of Single-wall Carbon Nanotubes (SWNTs) on Platinum Surfaces by Self-Assembling Techniques

Single-wall carbon nanotubes (SWNTs) are very interesting materials because of their morphology, electronic and mechanical properties. Its morphology (high length-to-diameter ratio) and electronic properties suggest potential application of SWNTs as anode material for lithium ion secondary batteries. The introduction of SWNTs on these types of sources systems will improve their performance, efficiency, and capacity to store energy. A purification method has been applied for the removal of iron and amorphous carbon from the nanotubes. Unpurified and purified SWNTs were characterized by transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). In order to attach carbon nanotubes on platinum electrode surfaces, a self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) was deposited over the electrodes. The amino-terminated SAM obtained was characterized by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), and Fourier-transforms infrared (FTIR) spectroscopy. Carbon nanotubes were deposited over the amino-terminated SAM by an amide bond formed between SAM amino groups and carboxylic acid groups at the open ends of the carbon nanotubes.This deposition was characterized using Raman spectroscopy and Scanning Electron microscopy (SEM).

Rosario-Castro, Belinda I.↗

Synthesis and characterization of novel Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} perovskite material and possible application as a cathode for low–intermediate temperature SOFCs

Highlights: • Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} was synthesized using sol–gel methods. • Material was thoroughly characterized using Raman, FTIR, XRD, HRTEM, SEM, and TGA. • Electrochemical performance showed the materials are a promising new cathode material for low temperature SOFC. - Abstract: A novel perovskite material, Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} was synthesized using a sol–gel technique. The materials were calcined at temperatures of 800 °C, 900 °C, and 1000 °C and then characterized using X-ray diffraction, Raman and infrared spectroscopy, high resolution transmission electron microscopy and scanning electron microscopy (SEM). The particle sizes and crystallite sizes increased with increasing calcination temperature and formed perovskite type materials with some separate magnetite and iridium oxide. The powders were used to assemble button cells using samarium doped ceria as the electrolyte and NiO/SDC as the anode materials. The electrochemical properties were investigated using a Fiaxell open flanges test set-up and a Nuvant™ Powerstat-05 potentiostat/galvanostat. The Ce{sub 0.8}Sm{sub 0.2}Fe{sub 0.9}Ir{sub 0.03}Co{sub 0.07}O{sub 3−δ} cathode material calcined at 1000 °C exhibited the most promising performance, with a maximum power density of 0.400 W/cm{sup 2}, a current density of 0.8 A/cm{sup 2}, and a corresponding area specific resistance of 0.247 Ωcm{sup 2} at 500 °C. The button cells were reasonably stable over15 h.

36 MATERIALS SCIENCE↗

Effect of the dielectric constant of a liquid electrolyte on lithium metal anodes

Lithium metal is considered one of the most promising anode materials for realizing high volumetric and gravimetric energy density, owing to the high specific capacity (~3860 mAh g -1 ) and the low electrochemical potential of lithium (-3.04 V vs. the standard hydrogen electrode). However, undesirable dendritic lithium growth and corresponding instability of the solid electrolyte interphase prevent safe and long-term use of lithium metal anodes. Here, this paper presents a simple electrolyte approach to enhance the performance of lithium metal batteries by tuning the dielectric constant of the liquid electrolyte. Electrolyte formulations are designed by changing the concentration of ethylene carbonate to have various dielectric constants. This study confirms that high ethylene carbonate content in a liquid electrolyte enhances the cycling performance of lithium metal batteries because the electric field intensity applied to the electrolyte is reduced in relation to the polarization of the electrolyte and thus allows smooth lithium plating and formation of a stable solid electrolyte interphase. Lastly, we believe that this approach provides an important concept for electrolyte system design suitable to lithium metal batteries.

25 ENERGY STORAGE↗

Anode-Free Rechargeable Lithium Metal Batteries

Anode-free rechargeable lithium (Li) batteries (AFLBs) are phenomenal energy storage systems due to their significantly increased energy density and reduced cost relative to Li-ion batteries, as well as ease of assembly owing to the absence of an active (reactive) anode material. However, significant challenges, including Li dendrite growth and low cycling Coulombic efficiency (CE), have prevented their practical implementation. Here, we report for the first time an anode-free rechargeable lithium battery based on a Cu||LiFePO4 cell structure with an extremely high CE (> 99.8%). This results from the utilization of both an exceptionally stable electrolyte and optimized charge/discharge protocols which minimize the corrosion of the in-situ formed Li metal anode.

anode-free↗

Modeling framework for multiphysics-multiscale behavior of Si–C composite anode

To achieve the urgent requirement for high energy density in lithium-ion batteries, Si-C composite anode has been spotlighted as one of the most promising alternatives for next-generation batteries. Additionally, a comprehensive computational model is indispensable in the developing process of the excellent performance of anode material due to the low-realizability, inconvenience, and high-cost of experiments. Herein, a simultaneous multiphysics-multiscale model aiming at the Si-C composite anode was developed. This model was then used to study the effects of Si percentage, mechanical constraint and charging rate in terms of electrochemical and mechanical performances. A better design to achieve high capacity was proposed based on the computational results. Results provide a powerful tool in the design, development, and evaluation of high energy density lithium-ion batteries.

25 ENERGY STORAGE↗

Lithium anode stable in air for low-cost fabrication of a dendrite-free lithium battery

Lithium metal, the ideal anode material for rechargeable batteries, suffers from the inherent limitations of sensitivity to the humid atmosphere and dendrite growth. Herein, low-cost fabrication of a metallic-lithium anode that is stable in air and plated dendrite-free from an organic-liquid electrolyte solves four key problems that have plagued the development of large-scale Li-ion batteries for storage of electric power. Replacing the low-capacity carbon anode with a safe, dendrite-free lithium anode provides a fast charge while reducing the cost of fabrication of a lithium battery, and increasing the cycle life of a rechargeable cell by eliminating the liquid-electrolyte ethylene-carbonate additive used to form a solid-electrolyte interphase passivation layer on the anode that is unstable during cycling. This solution is accomplished by formation of a hydrophobic solid-electrolyte interphase on a metallic-lithium anode that allows for handling of the treated lithium anode membrane in a standard dry room during cell fabrication.

25 ENERGY STORAGE↗

Operando Analysis of Gas Evolution in TiNb 2 O 7 (TNO)-Based Anodes for Advanced High-Energy Lithium-Ion Batteries under Fast Charging

TiNb 2 O 7 (TNO) is regarded as one of the promising next-generation anode materials for lithium-ion batteries (LIBs) due to its high rate capabilities, higher theoretical capacity, and higher lithiation voltage. Furthermore, this enables the cycling of TNO-based anodes under extreme fast charging (XFC) conditions with a minimal risk of lithium plating compared to that of graphite anodes. Here, the gas evolution in real time with TNO-based pouch cells is first reported via operando mass spectrometry. The main gases are identified to be CO 2 , C 2 H 4 , and O 2 . A solid–electrolyte interphase is detected on TNO, which continues evolving, forming, and dissolving with the lithiation and delithiation of TNO. The gas evolution can be significantly reduced when a protective coating is applied on the TNO particles, reducing the CO 2 and C 2 H 4 evolution by ~2 and 5 times, respectively, at 0.1C in a half-cell configuration. The reduction on gas generation in full cells is even more pronounced. The surface coating also enables 20% improvement in capacity under XFC conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Lithiophilic V 2 O 5 nanobelt arrays decorated 3D framework hosts for highly stable composite lithium metal anodes

The lithium metal anode has been considered to be an optimal anode material for high-energy-density battery system due to its ultrahigh specific capacity. However, the sharp dendrite growth and infinite volume expansion have significantly impeded its commercial application. In this paper, we propose that V 2 O 5 as the lithiophilic substance can be decorated onto 3D stable frameworks to fabricate dendrite-suppressed composite Li metal anodes via a molten Li infusion method. It is demonstrated that the energetic chemical reaction between V 2 O 5 and molten Li together with the capillary effect based on the nanostructure of interconnected V 2 O 5 nanobelt arrays contributes synergistically to the great Li affinity of the V 2 O 5 -Ni foam (V 2 O 5 -NF) host and facilitate the efficient and uniform intake of molten Li into the 3D framework. Benefitting from the homogeneous Li distribution in the framework, the decreased local current density of the electrode and the stable property of the host, dendrite-free Li stripping/plating behavior and alleviated volume fluctuation have been achieved for the Li-V 2 O 5 -NF composite anode. Compared with the bare Li anode, the as-obtained Li-V 2 O 5 -NF composite anode exhibits much stable stripping/plating profiles with low overpotential (~18 mV) for ultralong lifespan (1600 h) at a current density of 1 mA cm -2 in symmetric Li/Li cell. Furthermore, outstanding rate capability and long-term cycling performance (78.8% capacity retention after 500 cycles under 2 C) are obtained in full cells when coupled with Li 4 Ti 5 O 12 (LTO) cathodes, indicating a promising potential for practical application. Moreover, this work demonstrates that using a new lithiophilic material, V 2 O 5 , should be an effective method to construct high stable 3D Li metal anode for Li metal battery.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Thermionic emission and energy conversion

This project worked on development of a transformative heat-to-electricity conversion device based on thermionic energy conversion. The research provided a unique opportunity to transform the thermionics technology of the 1950-1990s by applying modern materials and 21st century wafer-scale fabrication methods. Research was conducted to further development of a thermionic energy converter based on modern microfabrication and new low work function anode materials that can surpass all other forms of direct heat-to-electricity conversion. This project completed the following goals: (1) Developed components for use in thermionic energy converters and electron emission devices, including electrode materials for electron emission and electron absorption with ultimate work functions below 5 eV; (2) Designed and fabricated thermionic devices for energy conversion and electron emission based on the components developed in (1); (3) Engineered test systems to characterize electronic, thermal, and mechanical properties of thermionic devices and electron emitters and their components, and test devices and components designed and fabricated in (1) and (2); and (4) Developed theoretical modeling capabilities in support of these technical objectives.

36 MATERIALS SCIENCE↗

CRADA Final Report: Ultralong Cycle Life and Ultrafast Charging Batteries to Electrify High Duty-Cycle, Mobile Platforms

As part of the Cyclotron Road program, Tyfast Energy Corp. aimed to investigate the Li 3 V 2 O 5 (LVO) anode material for next generation lithium batteries. State of the art and fast charging lithium-ion batteries are based on the lithium titanate or Li 4 Ti 5 O 12 (LTO) anode chemistry. LTO cells demonstrate fast charging times (<6 mins), long cycle life (>20,000 cycles), but at the expense of very low energy density (<200Wh/L, <80Wh/kg). Silicon anodes have the promise of achieving fast charging times, however, issues with cycling stability in combination with fast charging is unknown. LVO has unique properties that enable new performance window for lithium batteries. First, LVO operates at an average potential of 0.6V vs. Li/Li + , well above the Li-metal plating region allowing ultrafast charge capability without sacrificing safety. Second, the LVO has a high specific capacity of 250 mAh/g making battery pack energy density equivalent with current high-energy Li-ion chemistries.

25 ENERGY STORAGE↗

Modified bornite materials with high electrochemical performance for sodium and lithium storage

Mineral-based functional materials have attracted enormous attention due to the advantages of high production, good material consistency, environmental friendliness, and low cost. However, the efficient utilization of natural minerals for high-performance energy storage is rarely reported. Here, we demonstrate a mineral-derived anode material Cu 5 FeS 4 coated with carbon for both sodium-ion and lithium-ion batteries. The findings show that ball milling bornite in the presence of polyvinylpyrrolidone followed by optimal-temperature carbonization results in S, N-codoped Cu 5 FeS 4 particles with the desired surface properties, enhanced electronic conductivity, and abundant active sites that deliver high reversible capacity and maintain superior long-term cycling performance at a high current density of 2.0 A g –1 . This work sheds light on potential energy storage use cases for naturally abundant mineral-based materials.

25 ENERGY STORAGE↗

Impact of Li-Ion Battery Recycling on the Supply Chain

With the increasing demand of the lithium ion batteries (LIB), it is expected that supply of some critical metals used in Li-ion batteries such as cobalt and lithium will fall short in the near-term, or their prices could increase significantly in response to the high demand. Besides increasing mining and production activities, we believe that a closed-loop system with recycling at the end-of-life provides a pathway to lower environmental impacts and a source of high value materials that can be used in producing new batteries. This presentation reviews the current state of the LIB manufacturing supply chain, discuses evolution and supply chain issues for cathode and anode materials, addresses some issues associated with battery end-of-life, and sheds light on the importance of LIB recycling from the environmental and value chain perspectives. This presentation also discusses the expected benefits of recycling on the global LIB supply chain.

25 ENERGY STORAGE↗

Study on the Carbon Nanostructures for Nanosized Si Electrodes

Silicon (Si) has been considered as a next-generation anode material due to natural abundance, low operating potential (<0.5 V vs. Li/Li+), and high theoretical specific capacity of 4200 mAh g-1.[1] However, the electrochemical alloying reaction of Si involves large volume changes of 400% during lithiation and delithiation, causing cracking and pulverization of Si.[1] In addition, solid electrolyte interface (SEI) of Si anode experiences constant changes due to unstable SEI reactivity.[2] Considerable efforts have been made to design nanostructured Si materials to address the issues because nanostructuring can relieve the mechanical strain.[3] However, when compared to micrometer-sized active materials having sufficient electrolyte pathway through interparticle space, the nanoparticle (NP)-based electrodes tend to be densely packed. As mass loading is higher and electrode is thicker, ion transport issue can become more severe in the densely packed electrodes.[4] In this work, we will present studies on engineered porosity impacts performance in Si NP electrodes by altering carbon nanostructures. We explore the extreme limit of effectively non-porous electrodes using quasi-spherical, Si NPs, which result in densely packed electrodes when slurry is prepared with conventional carbon black. We engineer porosity using carbon nanostructures including multi-walled carbon nanotubes and carbon nanorods in place of conventional carbon black to create pore structure in Si NP-based electrodes. These experiments provide a correlation between mass loading, porosity and silicon utilization in Si NP-based electrodes. References: [1] C. K. Chan, H. Peng, G. Liu, K. Mcllwrath, X. F. Zhang, R. A. Huggins, Y. Cui, "High-performance lithium battery anodes using silicon nanowires", Nat. Nanotechnol., 2008, 3, 31, [2] J. D. McBrayer, M.-T. F. Rodrigues, M. C. Schulze, D. P. Abraham, C. A. Apblett, I. Bloom, G. M. Carroll, A. M. Coclasure, C. Fang, K. L. Harrison, G. Liu, S. D. Minteer, N. R. Neale, G. M. Veith, C. S. Johnson, J. T. Vaughey, A. K. Burrel, B. Cunningham, "Calendar aging of silicon-containing batteries", Nat. Energy, 2021, 6, 1164, [3] H. Wu, G. Zheng, N. Liu, T. J. Carney, Y. Yang, Y. Cui, "Engineering Empty space between Si Nanoparticles for Lithium-Ion Battery Anodes", Nano Lett., 2012, 12, 904, [4] X. Zhang, Z. Ju, Y. Zhu, K. J. Takeuchi, E. S. Takeuchi, A. C. Marschilok, G. Yu, "Multiscale Understanding and Architecture Design of High Energy/Power Lithium-Ion Battery Electrodes", Adv. Energy Mater., 2021, 11, 2000808

carbon nanostructure↗

Nickel/silicon core/shell nanosheet arrays as electrode materials for lithium ion batteries

Highlights: • Ni nanosheet arrays is the core and Si layer is the shell. • Ni nanosheet arrays act as a three-dimensional current collector to support Si. • Ni nanosheet arrays can improve the conductivity and stability of the electrode. • Ni/Si nanosheet arrays exhibit excellent cyclic and rate performance. - Abstract: Ni/Si core/shell nanosheet arrays are proposed to enhance the electrochemical lithium-storage properties of silicon. The arrays are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The arrays are micro-sized in height, which are constructed by interconnected Ni nanosheet as the core and Si coating layer as the shell. The electrochemical properties as anode materials of lithium ion batteries are investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The arrays can achieve high reversible capacity, good cycle stability and high rate capability. It is believed that the enhanced electrochemical performance is attributed to the electrode structure, because the interconnected Ni nanosheet can act as a three-dimensional current collector, and it has the ability of improving the electrode conductivity, enlarging the electrochemical reaction interface, and suppressing the electrode pulverization.

36 MATERIALS SCIENCE↗