bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electroactive Polymer for Reversible Overcharge Protection in Lithium-Ion Batteries
Authors: Wang Bin , Cheng Jianli 
Published: February 2020

Great improvement in the safety of lithium ion battery is needed to meet the full requirements of electric vehicles (EV). Among these safety hazards, overcharge has long been recognized as a primary concern because it can lead to dangerous events such as thermal runaway, fire and explosion. The electroactive polymer approach utilizes the unique electronic properties of the polymers to form a reversible resistive shunt between the current collectors and protect the cell from overcharging. The process is self-activated by voltage, and it does not pose interference during normal cell charge and discharge.
In this work, we report the recent progress in cell overcharge protection for high-energy-density lithium ion batteries. By incorporating the reversible electroactive polymers into highly porous membrane separators, we demonstrate that the composites can provide reversible and stable overcharge protection for a variety of cell chemistries. The results for the protection of Li1.05Mn1.95O4 or LiNi0.8Co0.15Al0.05O2 electrode will be discussed. Both cells were protected at a steady state voltage of 4.5 V for well over 100 cycles.

ACKNOWLEDGEMENTS

The authors would like to acknowledge the support from the Startup Foundation of China Academy of Engineering Physics, Institute of Chemical Materials (KJCX201301 and KJCX201306) and the Natural Science Foundation for Young Scientists of Sichuan province (No. 2014JY0202).
The authors would like to acknowledge the support from the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Freedom CAR and Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02- 05CH11231.
In Situ Diagnosis and Control of Li-Ion Batteries for Enhanced Safety
Authors: Zhang Guangsheng , Ge Shanhai , Xu Terrence , Wang Chao-Yang 
Published: February 2020

Safety of Li-ion batteries remains a critical challenge due to their high energy density and use of flammable electrolyte. The challenge is further propelled by their ever-increasing and demanding applications in electric vehicles (EVs). Recent high-profile events involving electric cars and airplanes that employ Li-ion batteries as main or auxiliary power sources lend further urgency to enhanced Li-ion battery safety.
We obtained insights of nonuniform temperature distributions in Li-ion battery cells through in situ diagnosis1. Inspired by those insights, we developed a reaction temperature sensing (RTS)-based control technique to enhance Li-ion battery safety. The RTS-based control is demonstrated to shut down an external short circuit event 3 times earlier than conventional surface temperature- based control and effectively prevent cell damage2.
We will apply the RTS-based control and in situ diagnosis of temperature distributions to other challenging safety scenarios including internal short circuit. The progress will be presented.

Reference

1. G. Zhang, L. Cao, S. Ge, C.Y. Wang, C. E. Shaffer, C. D. Rahn, In situ measurement of radial temperature distributions in cylindrical Li-ion cells, Journal of The Electrochemical Society,2014, 161 (10): A1499-A1507
2. G. Zhang, L. Cao, S. Ge, C. Y. Wang, C. E. Shaffer, C. D. Rahn, Reaction temperature sensing (RTS)-based control for Li-ion battery safety, Scientific Reports, under review
Probing Lithium-Ion Battery Safety in Mining Environments
Authors: Lipka Stephen M , Rogers Fon , Whitlow David Tyler , Bramel Taylor 
Published: February 2020

Lithium-ion batteries are increasingly ubiquitous in portable consumer electronic devices, including laptop computers, cellular phones, and tablet computers. Lithium-ion batteries are also finding widespread deployment in many additional applications and settings, including underground mining environments, where lithium-ion batteries are used as electrochemical power sources for cap lamps, and in tracking and communications equipment.1,2 Battery safety is of paramount importance in any portable electronic device regardless of setting, and is particularly significant in enclosed and isolated areas such as passenger aircraft, or in underground mining environments, where potentially explosive methane/air mixtures can be ignited by a simple spark, which can be caused by shorting and thermal runaway of lithium-ion batteries.
This presentation will summarize systematic abuse testing of different lithium-ion batteries used in underground mining safety and communication equipment, including lithium cobalt oxide (LiCoO2), lithium nickel manganese cobalt oxide (NMC), and lithium iron phosphate (LiFePO4) based cathode chemistries. Prismatic and cylindrical 18650 lithium-ion batteries were obtained from commercial vendors and subjected to both wedge and flat plate crush tests, in order to determine the relative safety of each cathode chemistry under two crush speeds and various states-of-charge (SOC). Battery voltage, case temperature and applied load were recorded for each crush test. Video recording of each crush test was also collected. In some cases, hard or soft electrical short circuits were caused by crushing the battery, resulting in thermal runaway, rapid temperature increases, and explosions or fires. Correlations will be drawn between choice of cathode chemistry, state-of-charge, type of crush test, and choice of atmosphere (air or methane/air mixtures), in order to determine the most suitable lithium-ion battery chemistry for underground mining applications.
References
1) Dubaniewicz, T. H. Jr.; DuCarme, J. P. Journal of Loss Prevention in the Process Industries.
2014, 32, 165.
2) Dubaniewicz, T. H. Jr.; DuCarme, J. P. IEEE Transactions on Industry Applications.
2013, 6, 2451-2460.
Integrated Multiscale Multiphysics Modeling of Dynamic Short Circuit Behavior in Large Lithium-Ion Batteries
Authors: Kim Gi-Heon , Yang Chuanbo , Pesaran Ahmad 
Published: February 2020

Scale-up of the battery raises the complexity of interactions among the physicochemical processes occurring in intricate geometries across wide range time and length scales. The entangled interplays critically affect the performance, safety, and reliability of the batteries. Violent incidents reported for lithium-ion batteries (LIBs) and consequent safety concerns are still the major hindrance for fast market penetration of LIB-powered electric drive vehicles. Most of safety incidents leading to a thermal runaway in lithium-ion batteries involve internal-short-circuit (ISC).
ISCs are caused either from a latent defect growing over time or from a sudden mechanical failure of internal cell structure that may occur during battery intrusion or crush. Puncture and crush response of a battery involves various aspects of physics. The Multiscale Multidomain (MSMD) model framework provides a modular architecture, facilitating flexible integration of multiphysics model components. At initial stage of an ISC, the faulted battery is electrochemically active. This is true even through a whole event if no severe consequence follows. As such, the electrochemical model is imperative to determine the battery dynamic response to short circuit. For an induced ISC, fault current and accompanied heat must be quantified properly in consideration of thermodynamic and kinetic factors, while capturing the electronic current pathways along the intricate LIB geometries. LIB component materials become thermally unstable under exposure to high temperatures. The abuse reaction kinetics model predicts the battery’s chemical responses. In this paper, we introduce an integrated multiphysics LIB safety response model built on the MSMD nonlinear multiscale multiphysics model framework, and apply the model to investigate electrical, thermal, chemical and electrochemical behaviors of large-format cells in various form factors while resolving dynamic evolution of internal short circuit.
(Invited) Functional Conductive Polymer Binders for High-Performance Silicon-Based Anodes in Lithium-Ion Batteries
Authors: Jia Zhe , Zhao Hui , Liu Gao 
Published: February 2020

Electrode design has been a key aspect to achieve the high energy and power density, and superb cycling performance. Current lithium-ion-batteries (LIBs) use intercalation materials such as LiCoO2 for the cathode and graphite for the anode, with a theoretical specific capacity of around 370 mAh/g. Si, with rich natural abundance, exhibits theoretically 10 times higher capacity (4200 mAh/g) than the graphite (370 mAh/g). However, the problem associated with Si-based materials is that they involve a large volume change during cycling,and poor electronic conductivity. Fully alloying Si on charge to form Li4Si results in an almost 300% volume increase. Because of this high volume change, the electronic integrity of the composite electrode is disrupted, and a high and continuous surface side reaction is induced, both leading to a drastic capacity fade.
Our state-of-the-art electrode materials design has made a big step forward to use a polymer binder to ensure the integrity of the composite electrode for a dimensionally stable laminate. The polymer binder plays a critical function in maintaining mechanical stability and electrical conduction during the lithium insertion and removal process. We proposed a specific designed conductive polymer structure to provide molecular-level electronic connections between the active material and the conductive polymer matrix. Not only cycling stability of the silicon is significantly enhanced, being conductive itself, the use of conductive polymer binder eliminates the necessity of conductive additive, which considerably increases the loading of active material.
This approach achieves unparalleled capacity retention during cycling. An underlying principle to use conductive polymer as a negative electrode binder was developed and implemented in the synthesis of the new conductive and adhesive binders Poly(9,9-dioctylfluorene-co-fluorenone-co-methylbenzoic ester) (PFFOMB). These binders are cathodically (reduction) doped in the Si electrode environment to achieve electrical conductivity. Adhesion groups have been incorporated into the polymer binder to improve the electrode’s integrity. Aldrich commercial nano-Si powder has been used with the conductive polymer binder to form a Si electrode, without the need for acetylene black conductive additive. The electrode demonstrated over 650 cycles between 1volt (V) and 0.01 V at the 2500 milliamp hours per gram (mAh/g)-Si with only 20% capacity fade (Fig. 1). The conductive polymer binders have opened a new paradigm of electrode design for Si materials: they provide molecular-level electrical interaction between the electrode matrix and active materials and accommodate volume expansion of high-capacity Si materials.

Figure 1
Spectroelectrochemical Studies of Charge Transfer Processes in Stable Nitroxyl Radical-Containing Polymers
Authors: Hughes Barbara Katherine , Braunecker Wade A. , Johnson Justin C. , Gennett Thomas 
Published: February 2020

The electrochemical redox reaction of stable organic polymer materials with unpaired electrons is a relatively new and exciting area of battery research. Specifically, stable nitroxyl radical-containing polymers have displayed excellent characteristics as the cathode-active material and have presented themselves as a low-cost and environmentally friendly alternative to the current Li-ion battery technologies. However, with the advancement of organic-radical battery technology there is a lack of fundamental understanding of the dynamics of charge transfer processes, electronic and ionic, within organic radical-containing polymers. In order to elucidate these mechanisms further, we have conducted extensive spectroscopic and spectroelectrochemical investigations of macromolecular systems containing nitroxide radicals.
We have employed potential modulated spectroelectrochemical techniques for our study of stable radical polymer systems whereby, kinetic information can be determined, specifically rates of charge transfer and ion diffusion within our polymer systems. A key factor determining the success of such experiments is that the material of interest exhibits a strong absorption coefficient and allows for measurement in the concentration regime conducive for electrochemical studies (typically up to 10 mM). For this reason, of the available stable nitroxyl radical systems, we have chosen first to study the oxidation of a nitronyl nitroxide derivative. To simulate an electrode architecture, spectroelectrochemical studies were performed in the solid state, and the efficacy of charge transfer was investigated as a function of film thickness, counter-ion size, and radical polymer composition. As we have developed a synthetic process to produce ordered systems of stable organic radicals in the form of fixed polymer brushes grown from transparent conducting substrates, the effects of nano- and mesoscale ordering of the polymer film on charge transfer dynamics will also be presented.
Conjugated Organophosphorus Materials As Electrodes for Organic Batteries
Authors: Reus Christian , Baumgartner Thomas 
Published: February 2020

The demand for environmentally benign, organic π-conjugated materials is constantly growing since they combine low cost and solution processability with light weight and mechanical flexibility. These features open up the opportunity to access new domains in contemporary organic electronics such as rechargeable organic batteries. The currently best established batteries are based on Li-ion technology and typically suffer from various disadvantages, for example (i) the use of expensive and toxic metal oxides (e.g. LiCoO2), (ii) slow kinetics of electrode reactions leading to extended charging times, and (iii) the danger of self-ignition resulting from heat generation during the Li-intercalation processes at the electrodes. To overcome these deficiencies, research is focused on the development of electrochemically active compounds for use in ‘plastic’ batteries. State-of-the-art organic electrodes feature well-known redox-active structural motifs that exhibit stable reduced or oxidized states, such as nitroxides,[1] quinones,[2] or viologens[3] (e.g., N,N’-dimethylviologen MV2+
; cf. Figure).
Recent research in the area of π-conjugated materials has shown that the incorporation of inorganic main group elements – in particular B, Si, and P – is an efficient strategy to obtain materials with intriguing properties for a host of most different practical applications.[4] Our group has of late designed new π-conjugated, ring-fused organophosphorus viologens such as the N,N’-dimethyl-2,7-diazadibenzophosphole oxide (phospha-MV2+
, cf. Figure) that show enhanced electronic characteristics for potential battery applications as compared to parent viologen MV2+
.[5] The materials’ properties of these compounds have been refined by further modifications of phospa-MV2+
in order to improve the applicability in cathodes and/or anodes. Half-cell cycling studies of fabricated electrodes against lithium metal shed light on the performance of the electrode materials with respect to their capacities under different C-rates for charging/discharging currents, cycle lives, and other performance criteria.

References

[1] Nishide, H.; Oyaizu, K. Science
2008, 319, 737-738.
[2] Zhu, Z.; Hong, M.; Guo, D.; Shi, J.; Tao, Z.; Chen, J. J. Am. Chem. Soc. 2014, 136, 16461-16464
[3] Sen, S.; Saraidaridis, J.; Kim, S. Y.; Palmore, G. T. R. ACS Appl.
Mater. Interfaces 2013, 5, 7825-7830.
[4] He, X.-M.; Baumgartner, T. RSC Adv.
2013, 3, 11334-11350.
[5] Durben, S.; Baumgartner, T. Angew. Chem. Int. Ed.
2011, 50, 7948-7952.

Figure 1
Modeling Multi-Scale Carbon Fiber Supports for Thin Film Bioelectrodes
Authors: Do Duyen Van Thuy , Wen Hao , Gumeci Cenk , Calabrese Barton Scott 
Published: February 2020

Carbon electrodes with their super electro-catalytic properties are commonly used in electrochemistry, especially in biomolecular redox reactions1. Electrospinning as a low cost, facile technique is applied to produce uniform carbon nanofibers between 150 nm and 1µm fiber diameter by pyrolyzing electrospun Polyacrylonitrile (PAN) fiber at 250°C and 1100°C. Varying the concentration of PAN in N,N-Dimethylformamide precursor solution changes the fiber diameter and leads to diversity in materials properties, such as surface area, void fraction and conductivity. These electrospun carbon nano fiber (ECNF) properties are characterized by SEM, BET, and four-point probe resistivity measurements.
Thin film Os+/2+ mediated electron in hydrogel immobilized glucose oxidase layer is coated on either single micro fiber 2 or free - standing carbon nanofiber mats (Figure 1) to study the effect of carbon fiber physical properties on electron transfer in mediated redox hydrogel bioanode. Electron transport via redox polymer Os+/2+ is enhanced by reducing the average hydrogel film thickness with uniform distribution of small fiber of high surface area (<1.6E3 cm-1 surface area per volume). A transport model is developed to give more insight into these correlations and yield more understanding of electron transfer mechanism in thin film porous electrode.

Figure 1
Nano-Structured Pd-Sn Catalysts for Alcohol Electro-Oxidation in Alkaline Medium
Authors: Zalineeva Anna , Serov Alexey , Padilla Monica , Martinez Ulises , Artyushkova Kateryna , Baranton Stève , Coutanceau Christophe , Atanassov Plamen 
Published: February 2020

The study of alcohols electrooxidation is of paramount importance not only for direct fuel cell and/or electrolysis cell applications, but also in order to gain the fundamental knowledge on reaction mechanisms for electrosynthesis applications.
Tin is known to be a high performance co-catalyst of noble metal for alcohol oxidation, particularly concerning the ethanol electrooxidation reaction in acidic medium. This property of tin in association with palladium was recently confirmed for the electrooxidation of methanol, ethanol, and ethylene glycol in alkaline medium.
Here, the electrocatalytic behavior of Pd1Snxcatalysts towards the electrooxidation of different C1, C2 and C3 alcohols is compared and discussed in terms of activity and reaction pathways: methanol and ethylene glycol since they are the simplest alcohol and polyol, respectively, ethanol and glycerol because they can both be produced from biomass, and isopropanol which only bears a secondary alcohol function, because it can be interesting for the development of “rechargeable” direct fuel cells.
Particularly, the occurrence of two possible mechanisms, a base-catalyzed one and a mechanism based on the ability of the catalytic surface to favor the adsorption and desorption of species at low potentials, is discussed, as well as the difference in activity comparing isopropanol and glycerol oxidation reactions.
For this purpose, active self-supported Pd1Snx catalysts are synthesized by the Sacrificial Support Method (SSM). Their catalytic activity towards the oxidation of C1 to C3 alcohols was determined in alkaline medium. The comparison of the activity allowed discarding a first base catalyzed deprotonation reaction of alcohols as rate determining step (rds), and spoke up for a mechanism involving a C-adsorption of carbon bearing an alcohol function. By comparing isopropanol and glycerol oxidation voltammograms, and on the basis of in situFTIR spectroscopy measurements, it has been shown that desorption of dihydroxyacetone could be the limiting step for glycerol oxidation at low potentials.

Acknowledgement: Anna Zalineeva thanks the Center for Emerging Energy Technologies, Farris Engineering Center (UNM) for assistance and technical support, and the County Council of Poitou-Charentes (France) for financial support.
Electrochemical Studies of Thin Films of Side-Chain Ferrocene-Containing Diblock Copolymers
Authors: Ito Takashi , Ghimire Govinda , Yi Yi , Derylo Maksymilian A , Baker Lane A 
Published: February 2020

This presentation will report the electrochemical properties of gold-supported thin films of polystyrene-poly(2-(acryloyloxy)ethyl ferrocenecarboxylate) diblock copolymers (PS-b-PAEFc) with different PAEFc volume fractions (f
PAEFc = 0.47, 0.30, 0.17). These polymers were synthesized by two-step atomic transfer radical polymerization. Thin PS-b-PAEFc films were prepared on planar gold substrates via spin-coating from their toluene solutions. Atomic force microscopy images of the resulting films showed the formation of PAEFc microdomains with different (lamellar, cylindrical and spherical) morphologies as anticipated from the volume fractions. Their electrochemical properties including the percentages of reactive ferrocene moieties and electron propagation efficiency (apparent diffusion coefficients) were assessed using cyclic voltammetry (CV) and chronocoulometry in 0.1 M TBAPF6/CH3CN. CV data showed redox peaks from the PAEFc moieties. PS-b-PAEFc (f
PAEFc = 0.47, 0.30) exhibited an increase in redox current with increasing film thickness, whereas PS-b-PAEFc (f
PAEFc = 0.17) showed a similar current regardless film thickness. This observation suggests (1) the redox reaction took place at PAEFc microdomains that direct contacted to the electrode surface; (2) relatively thick (> 50 nm) films of PS-b-PAEFc (f
PAEFc = 0.47, 0.30) comprised PAEFc microdomains penetrating across the films; (3) the CH3CN-swollen PS and PAEFc were permeable for counter anions so that the charge neutrality was satisfied upon the oxidation of the ferrocene moieties. The apparent diffusion coefficients in these films were small (in the order of 10-11 cm2/s), probably limited by the diffusion of counter ions and/or by inefficient electron propagation between adjacent ferrocene moieties within the PAEFc microdomains. Applications of electrode-supported PS-b-PAEFc films will also be presented.

Reference

G. Ghimire, Y. Yi, M. A. Derylo, L. A. Baker, T. Ito, manuscript in preparation.