bluuebunny/crossref_metadata_2025_split huggingface dataset:
MnCo2O4 Anchored on Magneli Phase Titanium Oxide As a Non-Carbon Cathode for Li-O2 Batteries
Authors: Yang Ruizhi , Cao Xuecheng , Sun Zhihui , Li Fan 
Published: February 2020

Development of highly effective and environmentally friendly battery technology is crucial to the energy storage system and electronic vehicle.[1,2] Recently, the aprotic lithium-oxygen (Li-O2) battery has attracted much attention due to its high specific energy density of 3500 Wh kg-1 (based on the mass of Li2O2) and a favorable potential of 3.0 V, which are defined by the chemistry of the reversible reaction Li + O2 ↔Li2O2.[3,4] The high specific energy density of Li-O2 battery renders it a promising candidate for the electrical vehicle with extended-range driving. One of the challenges in Li-O2battery is to find a catalyst that can improve the sluggish electrochemical kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during the discharge and charge process, respectively.[5]
Herein, we employ Magneli phase Ti4O7 as a support and construct a hybrid with MnCo2O4 (MCO) nanoparticles being anchored on the surface of Ti4O7 for the first time. This hybrid is employed as a non-carbon cathode material for Li-O2 batteries. The synergistic interaction between Ti4O7 support and MCO nanoparticles further promotes the catalytic activity and stability of the hybrid. Benefiting form these advantages, the as-synthesized Ti4O7-MCO hybrid exhibits excellent catalytic activity to decrease the voltage gap between discharge and charge. The Ti4O7-MCO presents excellent discharge performance when compared with other carbon-free cathode materials. Moreover, due to the excellent chemical durability of Ti4O7 in organic electrolyte and the interaction between Ti4O7and MCO, the hybird is very stable during the battery cycling without agglomeration and detachment.
The Discharge/charge profile, rate capability and cycling performance of Ti4O7-MCO are shown in Figure 1.

Figure 1. (a) Discharge/charge profile of Ti4O7-MCO cathode under different current densities; (b) First discharge/charge profile of Ti4O7-MCO, Ti4O7, C and C-MCO with a limited capacity of 500 mAh g-1; (c) Cycling performance of Ti4O7 cathode; (d) Cycling performance of Ti4O7-MCO cathode.

Acknowledgements

This work is supported by National Natural Science Foundation of China (51572181), the National Key Research and Development Program of China (2016YFB0100200)，Natural Science Foundation of Jiangsu Province, China (BK20151226).

References

[1] A. S. Arico, P. Bruce, B. Scrosati, J. M. Tarascon, W. Van Schalkwijk, Nat. Mater. 4(2005)366.
[2] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J. M. Tarascon, Nat. Mater. 11(2012)19.
[3] G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 1(2010) 2193.
[4] F. Y. Cheng, J. Chen, Chem. Soc. Rev. 41(2012)2172.
[5] Z.-L. Wang, D. Xu, J.-J. Xu, X.-B. Zhang, Chem. Soc. Rev. 43(2014)7746.

Figure 1
Study of Porous Carbon Nanofibers As Interlayer and As Standalone Binder-Free Sulfur Hosts for Li-S Batteries
Authors: Kalra Vibha 
Published: February 2020

In the first part of the talk, I will present our work on study of free-standing porous carbon nanofibers with tunable surface area and pore structure as an interlayer between the sulfur cathode and the separator to inhibit the shuttling of the intermediate polysulfides in lithium–sulfur (Li–S) batteries. Specifically, the effects of thickness, surface area, and pore size distribution of carbon nanofiber (CNF) interlayers on the performance of Li–S batteries have been studied. The carbon nanofiber interlayer not only reduces the electrochemical resistance but also localizes the migrating polysulfides and traps them, thereby improving the discharge capacity as well as cyclability. A high initial discharge capacity of up to 1549 mA h g−1 at C/5 rate, which is 92% of the theoretical capacity of sulfur, with 98% average coulombic efficiency and 83% capacity retention after 100 cycles was obtained.
In the second half of the talk, I will discuss our work wherein we directly incorporate sulfur into the carbon nanofibers as a host using an ultra-rapid (5-second) deposition technique. This procedure melts sulfur into carbon nanofiber mats, which play a significant role as a built-in current collector to provide uninterrupted electron transport pathways throughout the electrode without hindrance of insulating binding agents, thereby eliminating the need for any dead weight from the binders, interlayer or current collector. The large inter-fiber spacing facilitates electrolyte diffusion and provides sufficient space for the volume expansion during lithium-sulfur redox. The cathodes exhibit highly stable discharge capacities at 0.5C with 100% capacity retention over 150 cycles (~550 mAh g-1 after conditioning). This technique completely eliminates the need for slurry-based processing including the insulating binders, toxic solvent, or heavy current collector, producing an effective capacity of ~991 mAh g-1 at 0.5C over 150 cycles. Moreover, conventional sulfur melt deposition techniques require high temperatures (155-300 °C) and are very time consuming (~8-10h) while this ultra-rapid technique requires only 140 °C, 5 seconds, and a small application of pressure (~200 psi). The ultra-rapid method offers a practical approach to sulfur cathode fabrication into simple fiber electrodes compared to conventional techniques that require time-consuming deposition to integrate sulfur into highly complex nanostructures. Furthermore, this free-standing nature of the nanofiber-based design demonstrates a feasible route for evolving technologies like smart fabrics and wearable batteries.

Relevant Reference: Singhal, R.; Chung, S-H.; Manthiram, A.; Kalra, V. Free-standing Carbon Nanofiber Interlayer for High Performance Lithium-Sulfur Batteries. Journal of Materials Chemistry A, 2015, 3, 4530.
New Findings on the Lithium Ion Conduction Behaviors Depending on Tilted Grain Boundaries in Garnet-Type Li7La3Zr2O12
Authors: Shiiba Hiromasa , Zettsu Nobuyuki , Jalem Randy , Nakayama Masanobu , Teshima Katsuya 
Published: February 2020

Garnet-type Li7La3Zr2O12 (LLZO) and its derivatives are considered promising candidate materials for all-solid-state Li-ion batteries as solid electrolytes due to their high Li+ conductivities of around 10-4 S cm-1 at room temperature and wide electrochemical window. Despite the larger number of detailed studies utilizing various experimental and theoretical approaches, the experimentally evaluated Li+ conductivities did not precisely match the computationally predicted values. The discrepancy between the ion conductivities can be attributed to the ambivalent properties of grain boundaries (GBs). GB structure is a critical parameter that controls the macroscopic properties of materials. However, various technological limitations of both the experimental and theoretical approaches utilized for elucidating the Li+ conduction behavior of GBs have restricted our ability of reaching a deeper understanding of the processes occurring at the atomic level. In this study, we investigated the Li+conducting behaviors of various tilted GBs of cubic LLZO with a garnet framework by using molecular dynamics approaches.
Nine stoichiometric equilibrium GB models were used to determine Li+conductivity. It was found that the GB conductivity was smaller than the bulk one regardless of the orientation. In particular, the conductivities perpendicular to the GBs were characterized by the lowest values.
Some factors affecting Li conductivity near the tilted GBs may be related to their stability. The relationship between the structural distortions at the GBs and the Li+ conducting characteristics were evaluated in terms of the GB energies and radial distribution function for the La-La, Zr-Zr, and O-O interactions in the LLZO bulk and GBs. We found that the Li+ conductivities are highly correlate with the structural distortions at the GBs.
In order to elucidate the Li+ diffusion characteristics at the GBs in more detail, the variations of the atomic concentration near the GBs were calculated along the axis perpendicular to the GB surface. The atomic population at bulk region was constantly modulated, while that at GB region was anomalously dispersed. The average atomic concentration at the GBs was lower than that at the bulk. In particular, the observed decrease in the Li+ concentration suggests the formation of Li-deficient sites across the GB center, which represents the primary reason for the degraded ionic conductivity in the GB region. In fact, the Li ionic conductivity perpendicular to the GBs decreased with decreasing Li+ concentration at the GBs, which was caused by the slower diffusion of Li+.
Thus, preventing the distortion of the GB crystallographic structure and the related drop in the Li+concentration should be considered one of the top priorities when designing GBs with desirable properties.

Acknowledgement

This work was partially supported by CREST, JST Grant Number JPMJCR1322, Japan.
A Wearable Electrochemical Sensor to Monitor Progression of Wound Healing
Authors: RoyChoudhury Sohini , Umasankar Yogeswaran , Bhansali Shekhar 
Published: February 2020

An enzymatic electrochemical biosensor comprising the enzyme, urate oxidase (uricase, UOx), has been investigated for detection of real-time changes in uric acid. Uric acid is a key biomarker for monitoring severity of wounds, a complex process initiated to restore tissue damage.1 Although, tracking wound healing continues to be a challenge in healthcare; it is equally demanding. In existing technology, the time taken from the appearance of a wound to the commencement of an effective wound management plan can be lengthy, as laboratory tests can take days to complete. With its presence in different bio-fluids2, this work explores the continuous monitoring of systemic uric acid in human sweat. Electrochemical techniques like cyclic voltammetry and differential pulse voltammetry have been investigated for evaluating the success of the sensor on a wearable platform as a surrogate for wound healing. On this biosensor, hydrolysis of UA was monitored to detect the oxidation of its byproduct, H2O2. Results show that the use of a redox electron shuttle such as ferrocene carboxylic acid (FCA) or metal nano-particles enable electron transfer between the active site of the enzyme and the electrode. This work explores the possibilities of embedding the biosensor in wound dressing-gauze materials as substrates and investigates the effect and role of metal nano-particles on detection. It can measure very low volumes (0.5uL) of sweat showing that such low volumes are sufficient for systemic detection of uric acid at the wound vicinity. This non-invasive approach holds promise for tracking wound chronicity and can be beneficial towards shorter hospitalization time, costs and reduced outcomes of trauma, surgery, and amputations.3 The developed biosensor could facilitate treatment with an improved, comprehensive understanding of the recovery processes associated with healing.

References

1. R. A. Nery, B. S. Kahlow, T. L. Skare, F. I. Tabushi, and A. do Amaral e Castro, Arq. Bras. Cir. Dig., 28, 290–2 (2015).
2. X. Dong, Intl. J. Of Pharmaceutical Sciences And Research, 8, 925-29 (2017).
3. Cobb, M. J.; Chen, Y.; Underwood, R. A.; Usui, M. L.; Olerud, J.; Li, X., J. Biomed. Opt., 11, 064002 (10.1117/1.2388152) (2006).
The Synthesis and Application of Llzo Ultrathin Electrolyte Film
Authors: Yan Xufeng , Li Zhuobin , Han Weiqiang 
Published: February 2020

Compared with a conventional lithium-ion battery, all-solid-state battery exhibits excellent safety, which is the one of drawbacks of the conventional lithium-ion battery. The Garnet electrolyte Li7La3Zr2O12 (LLZO), as the typical representative of solid electrolyte, shows outstanding safety and electrochemical stability.
During the process of this work, the LLZO underwent the changes from micro-sized particles, nano-particles slurry, and the final ultrathin film. The micro-sized particles was obtained by the conventional solid state reaction. Nanoscale LLZO slurry was prepared using high energy ball-milling technology, with the addition of 1-Methyl-2-pyrrolidinone, LiN(CF3SO2)2, SPEEK-PSI-Li and Piuronic®F127. The LLZO ultrathin electrolyte film was obtained by the method of wet coating and drying out the solvent of LLZO slurry.
The as-prepared LLZO ultrathin film, with a thickness of several micrometers, was applied in the cell of Li/LLZO/LFPO. At room temperature, the battery showed a capacity of 160.4 mAh g-1 for the first discharge, which was about 94.4% of the theoretical capacity value. After 100 cycles, the cell provided a discharge capacity of 136.8 mAh g-1. At 60 ℃, the battery presented more stable electrochemical performance. The capacity loss during the cycles form the 2nd to 100th was only 0.06% (0.7 mAh g-1). The excellent performance could be attributed to the ultrathin solid electrolyte film.
Importance of Electronic Conductivity in the Reversibility and Rate Capability of Metal Oxide Lithium Battery Anodes
Authors: Palmieri Alessandro , Ng Benjamin , Oliveira Alexandra , Mustain William E. 
Published: February 2020

Lithium ion batteries are the leading technology in the portable electronic market; however, in order to make the transition from laptops and tablets to automobiles and grid storage, materials with higher volumetric and specific energy density are needed. Therefore, new Li battery materials is an area of intensive research focus. At the anode, graphite has served well as the ubiquitous choice for commercial electrodes to date due to the high reversibility of Li intercalation, which resulted in very high stability and cycle life. However, the theoretical capacity of graphite is low, and it is possible that graphite-utilizing lithium batteries may be not be able to meet targets for emerging applications. Therefore, new solutions have to be investigated to increase the energy density of lithium ion batteries, while not sacrificing their stability and cycling performance compared to modern cells.
In recent years, our group has focused on advancing metal oxide-based anode materials toward automotive targets. To reach these targets, it is important to investigate and understand the key parameters that increase reaction reversibility and rate performance. In this poster, we will show how the active material electronic conductivity plays a critical key role in both cycling performance and stability of metal oxide anodes. The electronic conductivity was controlled by adding advanced carbons (i.e. reduced graphene oxide and carbon nanotubes) to increase the inter-particle conductivity, while the intrinsic conductivity of the active material was manipulated by doping. Both of these strategies will be discussed.
More quantitatively, the electronic conductivity was probed by the Van Der Pauw Method and tied directly to the cycle life of lithium cells collected by chronopotentiometric charge/discharge curves. The nanostructural changes of the active materials were investigated by high resolution transmission electron microscopy (TEM), including identical location TEM. Finally, applying the lessons learned from these experiments, highly stable full cells with a metal oxide anode and lithium cobalt oxide cathode were achieved.
Synthetic Control of Crystallite Size of Silver Vanadium Phosphorous Oxide (Ag0.50VOPO4·1.9H2O): Impact on Electrochemistry
Authors: Huie Matthew M. , Takeuchi Esther S , Takeuchi Kenneth J , Marschilok Amy C 
Published: February 2020

This report describes a synthetic approach to control the crystallite size of silver vanadium phosphorous oxide, Ag0.50VOPO4·1.9H2O, and the impact on electrochemistry in lithium based batteries. Ag0.50VOPO4·1.9H2O was synthesized over a range of temperatures. X-ray diffraction (XRD) was used to confirm the crystalline phase and the crystallite size sizes. Particle size and morphology were characterized using scanning electron microscopy and surface area measurements. Galvanostatic reduction and intermittent discharge were used to evaluate functional capacity and resistance. This systematic study of electrochemistry and material properties shows that deliverable capacity and cell resistance are impacted by both interparticle and intraparticle transport properties.
Enhanced Cycle Performance of MnO2 Supercapacitors By Ultrasonic-Assisted Electrodeposition
Authors: Xu Cheng , Liu Jikang 
Published: February 2020

Among the various inexpensive and environmentally friendly candidates for supercapacitors, MnO2 has been investigated extensively due to its outstanding comprehensive performance. However, MnO2 exhibits poor cycle performance in many research work, which may possibly due to the dissolution of MnO2 during charge-discharge cycles. In this work, we report a facile and effective method to improve the cycle performance of MnO2 films by ultrasonic-assisted electrodeposition.
The MnO2 films were electrodeposited on Ni foam substrates without treatment (denoted as sample I), with post-ultrasonic treatment (denoted as sample II) and synchro-ultrasonic treatment (denoted as sample III). The structures of the MnO2 films are characterized by SEM and TEM. MnO2 nanowire clusters and nanosheet arrays can be observed in the samples prepared by post-ultrasonic assisted and synchro-ultrasonic assisted electrodeposition, respectively, while irregular nanosheets are inspected in the samples without ultrasonic assistance. The electrochemical testing of cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements show typical pseudocapacitive behaviors for all samples. Directly electrodeposited MnO2 film without ultrasonic assistance suffers from obvious attenuation in capacitance, which decreases about 37% from 230 F g-1 in 3000 cycles. Comparatively, the ultrasonically treated MnO2 films exhibit a maximum specific capacitance of 369 F g-1 and 325 F g-1 at 1 A g-1, respectively, which can maintain 98% and 86% up to 3000 cycles, respectively. The effects of the deposition current and ultrasonic time were also investigated. The enhancement in electrochemical performance is significant for the samples with ultrasonic-assisted treatment, suggesting the treated MnO2 films to be a promising choice for supercapacitors.

Figure 1
(Invited) Next Generation Strategy for Reproducible, Compliant Microelectrode Arrays
Authors: Pancrazio Joseph J. , Voit Walter E , Capadona Jeffrey R 
Published: February 2020

Implantable MEAs are an essential tool for the elucidation of the functional circuitry of the brain. These devices offer a means of simultaneously recording from neurons to elucidate modular and hierarchical processing, as well as neural circuitry involved in adaptation. In addition, MEAs have the potential to serve as a clinical neuroprostheses. MEAs implanted in cortex record from motor regions to enable control of devices, systems, and can restore control of the patients own paralyzed limbs when combined with functional electrical stimulation systems. The majority of MEAs, and especially those that are available commercially, are fabricated from silicon and leverage techniques associated with integrated circuit microfabrication and packaging. Using industry standard approaches, the features of MEAs can be reproducibly created and the resulting devices can be manufactured and disseminated. Two well-known approaches are MEAs initially developed at the University of Utah and at the University of Michigan now available to the neuroscience research community through Blackrock Microsystems and Neuronexus, respectively.
It is now widely understood that these devices exhibit limited long term viability where recordings fail after 6 months – 1 year after implantation. One of the causes for this failure is believed to originate from the chronic foreign body response from microglia and astrocytes which extends well beyond the normal acute inflammatory response following initial implantation. This foreign body response has often been attributed, in large part, to the mechanical mismatch that exists between the MEAs and the surrounding brain tissue as well as the feature size of the MEAs. In this presentation, we will discuss a novel type of MEA that achieves compliance by material properties, specifically MEAs created from shape memory polymers (SMPs) where formulations allow tunable and dynamic mechanical properties. SMPs can be fabricated which are stiff at room temperature, but soften by 1-2 degrees of magnitude once inserted in the brain. This strategy, which leverages conventional photolithography, can be utilized to create devices customized for recording and stimulation within cortical and deep brain regions. An important aspect of this strategy is that it provides a pathway for translation and dissemination of novel, manufacturable neurotechnology. This presentation will provide an overview of work to date to create and demonstrate compliant and flexible MEAs and the electrochemical characterization of these devices both in vitro and in vivo.
Detection of Bacillus Anthracis Spores in Water Using a Phage-Coated Piezoelectric Membrane
Authors: Lu Xu , Wang Liang , Hou Lei , Cheng Zhongyang 
Published: February 2020

Piezoelectric membrane, working as resonant device, was introduced as biosensor platform. The principle of this device is based on the frequency response of mass load due to the capture of anthracis spores by phage immobilized on the membrane surface. The responses of membrane in anthracis spores solutions were experimentally studied. It was found that the sensitivity of detection can be improved by using smaller membrane or by using high resonant mode of the membrane, which is in good agreement with the theoretical analyses.
Hexagonally Arranged Ag-Hemisphere Arrays with Rough Surface and the SERS Detection to Persistent Organic Pollutants
Authors: Tang Haibin , Meng Guowen , Wu Nianqiang 
Published: February 2020

Persistent organic pollutants (POPs) are highly toxic and harmful to human health and the ecological environment. As such, the rapid trace detection to POPs is very important. The surface enhanced Raman scattering (SERS) effect of nanostructures can greatly enhance the intrinsic Raman signal of these pollutants with rapid response. This is expected to achieve rapid trace detection to POPs using SERS spectrum technique, overcoming the shortcomings of traditional detection methods.
One of the most important challenges is to fabricate SERS substrates with high SERS activity and uniform signal response. Herein, we have fabricated orderly hexagonally arranged Ag-hemisphere arrays with rough surface (Ag nanoparticle@Au nanopartilcle, urchin-like Ag hemisphere, and flower-like Ag submicron particles) using anodic aluminum oxide (AAO) templates. These nanostructures show high SERS sensitivity and uniform signals for the detection of plasticizer molecules and polychlorinated biphenyls (PCBs, a type of POP).