bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Glucose/Oxygen Wearable Biofuel Cells Based on Poly(glycidyl methacrylate)-Grafted MgO-Templated Porous Carbon
Authors: Shitanda Isao , Fujimura Yuki , Kato Takanao , Suzuki Ryo , Loew Noya , Hoshi Yoshinao , Watanabe Hikari , Itagaki Masayuki , Tsujimura Seiya
Published: December 2020

There are a lot of recent researches on high power enzymatic glucose/O2 biofuel cells (BFCs). We have reported that the use of MgO-templated porous carbon (MgOC) at the electrodes of biofuel cells dramatically improves the output power [1-4]. Using MgOC can improve the effective electrode surface area, leading to increased current density and output density. Supporting enzymes on these types of porous materials is expected to lead to increased output density. In the past researches [1-4], the enzymes physically adsorbed inside the porous carbon gradually leach from the carbon surface after long-term operation or during the replacement of the fuel solution.

In this study, to prevent enzyme leakage, the enzyme or mediator were immobilized on the MgOC surface via multipoint covalent bonding; the grafting of polymers bearing pendant glycidyl groups was achieved by the polymerization of glycidyl methacrylate (GMA), initiated by electron beam irradiation on the carbon surface. Poly(glycidyl methacrylate) (poly(GMA)) bearing pendant glycidyl groups, grafted on the surface of MgO-templated carbon, is useful for forming strong multipoint covalent bonds with amino functional groups on the surface of flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH), Azure A and aminoferrocene.

For example, the immobilized FAD-GDH can generate glucose-oxidation catalytic current using 1,2-naphthoquinone (12NQ) as the redox mediator, which is also captured on the electrode surface. The catalytic current is more stable than that obtained using the FAD-GDH-MgOC electrode without poly(GMA) because the leaching of FAD-GDH and 12NQ is suppressed by the enzyme capping effect.

The BFC performance using the anode measured in 1.0 M phosphate buffer (PBS) containing 100 mM glucose exhibited the open circuit voltage of 0.8 V, maximum power density of 1.4 mW/cm2, and maximum current density of 4.25 mA/cm2.

In the present paper, we totally discuss three types glucose/oxygen biofuel cells based on the poly(glycidyl methacrylate)-grafted MgO-templated porous carbon.

References

[1] S. Tsujimura et al., Electrochemistry 83 (2015) 372.

[2] I. Shitanda et al., Electrochemistry, 83 (2015) 329.

[3] I. Shitanda et al., Journal of Electrochemical Society, 166 (2019) B1063.

[4] I. Shitanda et al., Journal of Power Sources, 436 (2019) 226844.

Acknowledgement

This work was partially supported by JST-ASTEP Grant Number JPMJTS1513, JSPS Grant Number 17H02162 and Private University Research Branding Project (2017-2019) from Ministry of Education, Culture, Sports, Science and Technology, and Tokyo University of Science Grant for President's Research Promotion．
(Invited) Skin-Interfaced Wearable Electrochemical Sweat Biosensors
Authors: Gao Wei
Published: December 2020

The rising research interest in personalized medicine promises to revolutionize traditional medical practices. This presents a tremendous opportunity for developing wearable devices toward predictive analytics and treatment. In this talk, I will introduce our recent advances in developing fully-integrated skin-interfaced flexible biosensors for non-invasive molecular analysis. Such wearable biosensors can continuously, selectively, and accurately measure a wide spectrum of sweat analytes including metabolites, electrolytes, hormones, drugs, and other small molecules. These devices also allow us to gain real-time insight into the sweat secretion and gland physiology. The clinical value of our wearable sensing platforms is evaluated through multiple human studies involving both healthy and patient populations toward physiological monitoring, disease diagnosis, and drug monitoring. This talk will also feature our very recent works on laser-engraved lab on the skin and biofuel powered battery-free electronic skin toward metabolic/nutritional management as well as dynamic stress monitoring. These wearable and flexible devices could open the door to a wide range of personalized monitoring, diagnostic, and therapeutic applications.
(Invited) Peptide Screening for the Regulation of Gold Nano-Biomineralization Using Peptide Array Technology
Authors: Tanaka Masayoshi
Published: December 2020

Some peptides have been utilized in the functionalization of nanomaterials, the control of nanoparticle (NP) synthesis, as biotemplating for morphological control, and biocatalysts for the NP crystallization. The catalytic peptides used for NP synthesis, named biomineralisation peptides, generally demonstrate high specific binding to a target material, and are screened from a peptide library (e.g. phage display library). However, the properties of NPs synthesized, using such biomineralization peptides, cannot be predicted from screening process; thus the development of a rational peptide screening method which can be used to synthesize NPs with specific morphological and optical properties would greatly expand the potential of biomineralization peptides.

Herein, we focused on gold, which is also used as an electrode material for sensors, and developed an efficient method for identifying peptides that bind to gold nanoparticles (AuNPs). Using the spot synthesis-based peptide array technique, AuNP binding activities of approximately 1,800 peptides were firstly evaluated and revealed various activities ranging from positive (high-affinity binding peptides) to negative (weak- or null-affinity binding peptides). Among 50 peptides showing the highest AuNP binding activity, 46 sequences showed the presence of tryptophan-based motifs including W[Xn]W, H[Xn]W, and W[Xn]H (W: tryptophan, X: any amino acid, n: 1 to 8 amino acid residues), whereas none of these motifs was found in the WORST50 peptides. Notably, by using peptide array comprising high-binding peptides, more than 100 sequences were discovered at once to have AuNP synthetic ability on the peptide array. In addition, the image analysis of peptide array disclosed the optical property information from synthesized AuNPs at each peptide spot. Subsequently, screened peptides were demonstrated as suitable agents for the one-pot aqueous-phase synthesis of AuNPs and optical properties shown in the solution were consistent with that of array. Furthermore, obtained AuNPs were characterized to three types regarding to their optical properties, which are red, green and blue. The particle sizes were around 8.9, 2.6 and 34.7 nm respectively. These techniques are show potential not only in improved AuNP biomineralizations, but also could be used in the synthesis of other inorganic nanomaterials, such as semiconductor and magnetic particles in ambient condition. In this talk, I will also present some research examples using peptide array technology for biosensor development.

References

Tanaka, M., et al., (2017) Acta Biomaterialia, 49, 495-506.

Tanaka, M., et al., (2019) Nanoscale Adv., 1, 71-75.

Tanaka, M., et al., (2020) Int. J. Mol. Sci., 21(7), 2377

Komikawa, T., et al., (2020) Biosens. Bioelectron., 153, p112030

Figure 1
Enhanced Osteogenic Differentiation of Human Mesenchymal Stem Cells on Ti Surfaces with Electrochemical Nanopattern Formation
Authors: Kim Doohun
Published: December 2020

To increase bone regeneration around a titanium implant, nanopattern surfaces with 10 nm nanopores in 120 nm dimples were produced by electrochemical nanopattern formation (ENF) [1].

The ENF surfaces were obtained by removing the TiO2 nanotube layers prepared by an anodization process. To determine the effect of the ENF surface in vitro, cell proliferation assays, alkaline phosphatase (ALP) activity assays, Alizarin red staining, western blotting, and immunocytochemistry were performed. Atomic force microscopy and scanning electron microscopy analysis showed that the ENF surface had an ultrafine surface roughness with highly aligned nanoporous morphology. In vitro, human mesenchymal stem cells exhibited increased cell proliferation and enhanced expression of osteogenic molecules such as ALP, osteopontin, and osteocalcin on ENF surfaces compared to the TiO2 nanotube surfaces.

In this presentation, the performance of ENF surfaces for an osteointegrative implant material will be discussed.
(Invited) Mining Microbes to Engineer Novel Biosensor Devices
Authors: Kuzmanovic Uros , Ortiz Luis , Baer R , Grazon Chloe , Chen Mingfu , Addokhi Abdurrahman , Bono Michael , Charles Roger , Sankar Karthika , Petherbridge Rachel , Densmore Doug , Allen Karen , Klapperich Catherine M. , Grinstaff Mark W , Galagan James
Published: December 2020

We have developed a strategy for biosensor engineering that leverages an enormous and untapped reservoir for portable and inexpensive sensing parts: microbes. Microbes have evolved over 3 billion years to detect an array of stimuli relevant to biology, biotechnology, and our environment. They do so via proteins that have several desirable characteristics including: (1) they are already miniaturized and therefore portable, (2) they are inexpensive to generate with standard cloning techniques, (3) they can respond rapidly and with high sensitivity and specificity, and (5) they can be integrated into low cost electronic devices.

Our strategy employs genomics and functional assays to screen microbial samples for sensor proteins specific for a target analyte, and to isolate the genes for these proteins. In addition to screening isolated single bacteria, our methods enable metagenomic screening of the full diversity of any microbiome, including unculturable and unidentified bacteria. Once harvested, proteins are optimized for their sensing characteristics using protein engineering, directed evolution, and computational modeling. We then develop these proteins into sensor devices using existing and novel transduction approaches.

The talk will describe our screening approach and its application to the development of multiple sensors from two broad classes of microbial proteins: allosteric transcription factors and redox enzymes. The sensors discovered and developed through our approach can be readily deployed into a range of applications for portable, real-time, and inexpensive biosensing. The talk will preview our ongoing work to deploy our novel sensors into a wearable device for sweat and interstitial fluid monitoring.

Figure 1
Identifying Challenges and Methods for Mitigation in No-Cobalt LiNiO2 Cathode Materials
Authors: Mu Linqin , Lin Feng
Published: December 2020

Cathode materials such as layered oxides play a crucial role in determining the energy density and safety of lithium ion batteries. LiCoO2 based cathode materials, which have been dominating the batteries in portable devices for many years, are facing unique issues, such as high cost and child labor problems in cobalt mining. As an alternative solution, LiNiO2, isostructural to the commercial LiCoO2, extensively explored in the 1990s, has recently attracted renewed attention in quest of extremely low-Co or completely Co-free layered cathodes to reduce the reliance on high-cost toxic Co resource. However, with the high nickel content, the issues such as phase transformations, anisotropically periodic volume changes, highly reactive surfaces, oxygen release, and poor thermal stability have become pronounced. These challenges, associated with the unstable bulk and surface chemistry, have hindered the implementation of LiNiO2 in practical batteries over the last few decades. In this presentation, we will present the multiscale doping strategies in LiNiO2 to improve the electrochemical performance through bulk and surface stabilizer. We will also elaborate our approach to engineer the dopant distribution in individual battery particles. In addition, we systematically investigate how the surface chemistry of LiNiO2 based materials changes with various environments, including human exhalation, sample storage, sample preparation, electrochemical cycling, and surface doping. Our results demonstrate that the surface of these materials is highly reactive and prone to alter at various stages of sample handling and characterizations. We highlight that more efforts should be devoted towards the development of highly stable CEIs either by cathode surface coating, doping, electrolyte modification or combining multiple strategies.
2D MoWS2 Alloy As Multifunctional Electrocatalyst for High Performance Cathode in Li-S Batteries
Authors: Bhoyate Sanket , Choi Wonbong
Published: December 2020

The lithium sulfur (Li-S) battery is an energy storage device beyond Li-ion batteries which presents unique polysulfide chemistry resulting in high theoretical capacity of 2,600 Wh/kg. However, the unwanted shuttling of soluble lithium polysulfides (LiPSs) such as Li2S8 and Li2S6, corrodes the Li anode by forming an inactive sulfide layer and limit the life cycle of the Li-S battery. In previous studies, pristine 2D materials were used as the catalyst to anchor the polysulfides in cathodes and prevent the shuttling effect. The weight loading and concentration of catalysts in cathode was too high for the practical application in Li-S battery. In our study, we synthesized novel lightweight 2D Mo0.5W0.5S2 catalyst on CNT paper as a sulfur host cathode to efficiently catalyze the polysulfide reactions. Our catalyst shows mixed 2H-1T phase resulting in enhanced polysulfide binding, conversion and electron transfer resulting in improved specific capacity of 1,228 mAh/g at 0.1 C. The accelerated transformation of the dissolved polysulfides to the insoluble LiPSs resulted in an improved cyclic stability upto 400 cycles, as compared to 100 cycles for pristine cathode. Our study shows novel approach with binder-free ultra-light weight catalytic cathodes for practical application of Li-S battery.
Polymer-Inorganic Nanocomposite Coating with High Ionic Conductivity and Transference Number for Stable Lithium Metal Anode
Authors: Fu Chengyin , Battaglia Corsin
Published: December 2020

Lithium metal is an ideal candidate for battery anodes due to its high specific capacity (3860 mAh g–1) and low electrochemical potential (–3.04 V). However, non-uniform lithium electrodeposition causes low Coulombic efficiency, poor cycling stability, potential safety issues, and has hindered the commercialization of lithium metal batteries at scale. The parasitic reaction of lithium metal with liquid electrolytes results in the formation of a solid electrolyte interphase (SEI). During cycling, the SEI tends to break continuously, exposing unreacted lithium metal to the electrolyte. This not only promotes non-uniform lithium plating and stripping, but also leads to further SEI formation, which consumes the liquid electrolyte. In addition, the detachment of dendritic lithium from the bulk lithium electrode produces electrically isolated 'dead' lithium during lithium stripping, which no longer participates in the cell reaction. Dendritic lithium and 'dead' lithium formed during cycling largely increase the surface area of the lithium metal anode and consequently accelerates electrolyte consumption. These mechanisms lead to rapid capacity fading and cell failure due to either the complete consumption of the electrolyte or the complete conversion of the lithium metal anode to 'dead' lithium. The formation of lithium metal dendrites can also causes abrupt cell short circuit, which results in thermal runaway. Therefore, a stable interface on lithium metal electrode that enables uniform lithium electrodeposition is the key for the development of lithium metal batteries.

Here, we report a nanocomposite coating for the lithium metal protection, which consists of nano-sized LiF particles embedded into a PEO polymer matrix as shown in the inset of the following figure. The nano-sized LiF particles ensure high interface area, which provides lithium-ion pathway throughout the composite. The LiF/PEO nanocomposite coating offers exceptionally high ionic conductivity of 0.97 mS cm–1 and high lithium-ion transference number of 0.77 at room temperature in contact with a carbonate-based liquid electrolyte. Both properties are key to realize uniform lithium plating and stripping and prevent lithium dendrite formation. Lithium metal electrodes coated with this protective coating enable stable lithium plating and stripping at 1 mA cm–2 for over 1000 h. As shown in the following figure, a full cell with the coated lithium metal anode and a NMC622 cathode with an areal capacity of 1 mAh cm–2 shows much improved specific capacity and cycling stability. The cell exhibits a high initial capacity of 135 mAh g–1 and a capacity retention of 83% after 500 cycles at 1 mA cm–2. Even at a high current density of 3 mA cm–2, the full cell shows an initial capacity of 125 mAh g–1 and a capacity retention of 74% after 300 cycles.

Figure 1
Conducting Polymer Composites As Multifunctional Electrode Matrices for Lithium-Ion Batteries
Authors: Nguyen Van At
Published: December 2020

The rising number of lithium-ion battery cells fabricated to power electric vehicles has raised concerns about the environmental impacts of battery electrode fabrication process. Typically, N-Methyl-2-pyrrolidone (NMP) solvent is used to blend active materials and electrode matrices, which are normally polyvinylidene fluoride/carbon-black (PVDF/C) mixtures. The use of NMP solvent, however, requires extensive energy for electrode drying and toxic solvent recovery. In addition, the PVDF/C electrode matrix offers weak interactions with active materials, which results in poor morphological integrity and rapid capacity fading, especially for high-volume-change electrode materials. Using water-processable binders such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) has been proven to enable a greener electrode-casting process as well as improve electrode performance. However, the electrical conductivity of these electrodes relies mainly on carbon additives, which are subjected to agglomeration and volumetric-capacity reduction. In this study, new electrode matrices are developed from in situ polymerized polypyrrole:carboxymethyl-cellulose (PPy:CMC) composites with water-processable and electrical-conductive features. By forming a composite structure in which CMC acts as an anionic dopant for PPy conducting polymer, the PPy:CMC composites show good electrical conductivity, allowing them to be used as mono-component electrode matrices. As a result, carbon-additive-free LiCoO2/PPy:CMC electrodes can cycle at different C-rate. More importantly, the PPy:CMC composites enable aqueous slurry electrode casting, addressing the environmental pollution associated with NMP solvent utilization. The study introduces another potential application of conducting polymer composites in Li-ion batteries.

Keywords: aqueous electrode casting, conducting polymers, polypyrrole.
Impact of Nickel on Next-Generation Li-Rich Oxide Cathodes for Li-Ion Batteries
Authors: Ting Michelle , McCalla Eric
Published: December 2020

As developments in lithium-ion batteries have focused on improving energy density, cycle life, and reducing cost, an important class of layered oxides with excess lithium, Li[Li,Ni,Mn,Co]O2, has been heavily studied as a next-generation electrode material. However, our limited understanding of the underlying electrochemical mechanisms hinders our ability to mitigate the negative impacts of these mechanisms, and has to date prevented commercialization. Previous studies have shown that these materials show a myriad of simultaneous mechanisms including changes in the nickel oxidation state, reversible oxygen redox accounting for capacities exceeding the theoretical limit1, oxygen gas release decreasing cycle efficiency2, as well as structural transformations leading to voltage fade3. Due to this complex mixture of electrochemical processes, model systems have been used extensively to observe these processes one at a time.

This work on model systems is continued here by studying materials that show both nickel and oxygen redox but no structural transformations during cycling. This builds on work performed on Li-Fe-Sb-O and Li-Fe-Te-O where oxygen gas release was found to reduce Fe during charging of the electrode, an unexpected observation that has not been seen in other materials until the present study4. Given that nickel, and not iron, is of interest for next-generation materials, herein we use Li-Ni-Sb-O and Li-Ni-Te-O as model systems to better understand the electrochemical consequences of combining Ni and O redox processes during cycling. Herein, we show extensive electrochemical tests, ex-situ powder X-ray diffraction, online electrochemical mass spectrometry, X-ray absorption near-edge spectroscopy (XANES) and X-ray photoemission spectroscopy (XPS). Results show limited oxygen release takes place from the particle surfaces only, coupled with a marked contrast between the nickel oxidation states at the surface (as seen by XPS) and those of the bulk of the particles (seen with XANES). XPS data also demonstrates a reduction of surface nickel during oxygen gas release, confirming that the mechanism identified with Li-Fe-Sb-O does in fact occur in Ni-containing materials, though this is limited to the particle surface. Despite this surface effect, the reversibility of the nickel in the bulk is lost resulting in poor long-term cycling. Given that a great deal of work is currently being done to maximize the amount of nickel in next-generation electrode material, the consequences of nickel use in Li-rich oxides observed here are of high importance to further our understanding of these important materials.

References

1. McCalla, E. et al, Science 2015, 350 (6267), 1516.

2. Jung, R. et al, Journal of The Electrochemical Society 2017, 164 (7), A1361-A1377.

3. Gallagher, K. G et al, Electrochemistry Communications 2013, 33, 96-98.

4. McCalla, E. et al, Journal of the American Chemical Society 2015, 137 (14), 4804-4814.
Effect of N-S-Functionalization of Graphite Electrode on Electrochemical Performance of Vanadium Redox Flow Battery
Authors: Lim Sung Nam , Kim Kiyoung , Woo Ju Young , Song Shin Ae
Published: December 2020

The vanadium redox flow battery (VRFB) is under consideration as a promising energy storage system because of its flexible design, long lifetime, and safety against explosion. The electrode in a VRFB plays the essential role of providing reaction sites, which mainly affect the polarization of the system. Insufficient active sites on the surface of the electrode, specifically that made of carbon-based material such as graphite felt and carbon paper, leads to high polarization and poor electrochemical performance. Therefore, several groups have studied methods of electrode surface modification aimed at increasing the number of active sites, such as acid or thermal treatment and introducing of electrocatalyst (noble metal, metal oxide, or carbon-based material) on the electrode surface. In this study, we report a simple and easy method for nitrogen-sulfur dual functionalization on the graphite felt surface to enhance the energy efficiency of VRFB via self-polymerization and graft method. In addition, surface properties were investigated using various analytical techniques, and effect of dual functionalization was examined through comparison with the nitrogen functionalized graphite felt
Hydrogen Adsorption on Pristine Graphene at Room Temperature
Authors: Tokarev Andrey , Kureshi Sahida , Kjeang Erik , Cannon Mark , Quan Grace
Published: December 2020

We present a theoretical study of hydrogen adsorption on pristine graphene in the range of 0.1 to 50 MPa pressure at room temperature of 300 K by means of high accuracy molecular dynamics (MD) simulation in the LAMMPS software package1. For that we developed a novel technique of fast Force Field (FF) construction from quantum calculations. For the task, graphene-hydrogen interaction potential, constructed from quantum Density Functional Theory (DFT) calculations, was accompanied by Morse potential approximation of Silvera-Goldman potential2 for hydrogen-hydrogen interaction. We found that excessive hydrogen adsorption reaches maximum of 1.96 w.t. % at 30 MPa pressure. The isotherm of excessive hydrogen adsorption is well described by Langmuir isotherm with addition of negative linear term to account for excessive nature of adsorption. Comparison with literature data3-6 is provided.

References:

Plimpton, J. Comp. Phys., 117, 1 (1995).

F. Silvera and V. V. Goldman, J. Chem. Phys., 69, 4209 (1978).

Kowalczyk, H. Tanaka, R. Hołyst, K. Kaneko, T. Ohmori, and J. Miyamoto, J. Phys. Chem. B, 109, 17174 (2005).

Patchkovskii, J. S. Tse, S. N. Yurchenko, L. Zhechkov, T. Heine, and G. Seifert, PNAS, 30, 10439 (2005).

Srinivas, Y. Zhu, R. Piner, N. Skipper, M. Ellerby, and R. Ruoff, Carbon, 48, 630 (2010).

C. Ruiz-García, J. Pérez-Carvajal, A. Berenguer-Murcia, M. Darder, P. Aranda, D. Cazorla-Amorós, and E. Ruiz-Hitzky, Phys. Chem. Chem. Phys., 15, 18635 (2013).

Figure 1
Interfacial Evolution of Layered Oxides in Li-Ion Batteries: Chemical Transformation of Thin-Film Cathodes
Authors: Wan Gang , Steinrück Hans-Georg , Mars Julian Emanuel , Ma Lin , Franklin Joseph , Schroeder Marshall , Pollard Travis , Borodin Oleg , Xu Kang , Toney Michael F
Published: December 2020

High-voltage cathodes (> 4.5 V) are key components of next-generation Lithium-ion batteries (NG-LIBs). However, their full potential has been hampered by limited knowledge of the underlying chemistry and physics of the buried cathode/electrolyte interface. In particular, the stabilization of the cathode surface under highly oxidizing potentials is still under intense investigations due to a lack of mechanistic understanding of the degradation mechanisms and limited success in development of stabilization strategies. To tackle this challenge, we combined advanced surface-sensitive X-ray scattering and spectroscopies, in conjunction with mass spectrometric and electrochemical characterizations using model, single-crystal, thin-film LiNi0.5Mn0.3Co0.2O2 electrodes and high-purity electrolytes. As evidenced by the interfacial probes, significant transforms on the chemical and electronic properties of Ni and Co sites in cathode films have been observed when subject to carbonate-based solvents and electrolytes at open circuit conditions. Elucidation of the structural and chemical evolution in thin-film cathodes highlights hydrogenation of the layered cathodes by the protons generated from the interfacial degradation of carbonate-based electrolyte. This study unravels the nature of the hydrogenation reaction between cathode surface and carbonate-based solvents, which we relate to the transition-metal-dependent chemical degradation in cathode components. Molecular-level insights into the proton-transfer induced interfacial transformation and the stabilization of cathode surface via tuning the solvent properties with functional additives will also be discussed. Our studies offer foundational knowledge of the interfacial transitions and stabilization of cathode that can be translated to the rational design of improved NG-LIBs chemistries and electrolytes.
Critical Factors Dictating Reversibility of the Zinc Metal Anode
Authors: Ma Lin , Schroeder Marshall A. , Pollard Travis P , Borodin Oleg , Ding Michael S , Sun Ruimin , Cao Longsheng , Ho Janet , Baker David R , Wang Chunsheng , Xu Kang
Published: December 2020

With high energy density and improved safety, rechargeable battery chemistries with a zinc (Zn) metal anode offer promising and sustainable alternatives to those based on lithium metal or lithium ion intercalation/alloying anode materials; however, the poor electrochemical reversibility of Zn plating/stripping, induced by parasitic reactions with both aqueous and non-aqueous electrolytes, presently limits the practical appeal of these systems1. Although recent efforts in rechargeable Zn metal batteries (RZMBs) have achieved certain advancements in Zn metal reversibility2,3, as quantified by the Coulombic efficiency (CE), a standard protocol for CE has not been established, and results across chemistries and systems are often conflicting. More importantly, there is still an insufficient understanding regarding the critical factors dictating Zn reversibility.

In this work, a rigorous, established protocol for determining CE of lithium metal anodes4 is transplanted to the Zn chemistry and is used for systematically examining how a series of factors including current collector chemistry, current density, temperature, and the upper voltage limit during stripping affect the measured reversibility of different Zn electrolytes. With support from density functional theory calculations, this standardized Zn CE protocol is then leveraged to identify an important correlation between electrolyte solvation strength toward Zn2+ and the measured Zn CE in the corresponding electrolyte, providing new guidance for future development and evaluation of Zn electrolytes.

Figure 1 shows a schematic of proposed method, including initial results for some of the most promising Zn electrolytes reported in the literature. The capability of supporting Zn plating/stripping is differentiated clearly among these selected Zn electrolytes here.

Reference

1. Blanc, L. E., Kundu, D. & Nazar, L. F. Scientific Challenges for the Implementation of Zn-Ion Batteries. Joule
4, 771–799 (2020).

2. Wang, F. et al. Highly reversible zinc metal anode for aqueous batteries. Nat. Mater.
17, 543–549 (2018)

3. Naveed, A., Yang, H., Yang, J., Nuli, Y. & Wang, J. Highly Reversible and Rechargeable Safe Zn Batteries Based on a Triethyl Phosphate Electrolyte. Angew. Chemie Int. Ed.
58, 2760–2764 (2019).

4. Adams, B. D., Zheng, J., Ren, X., Xu, W. & Zhang, J.-G. Accurate Determination of Coulombic Efficiency for Lithium Metal Anodes and Lithium Metal Batteries. Adv. Energy Mater.
8, 1702097 (2018).

Figure 1
Investigation of Ethylene Carbonate Free Electrolyte for L4Ti5O12 Vs LiNi0.6Mn0.2Co0.2O2 Multi-Layer Pouch Cells
Authors: Hoffmann Jennifer , Payne Martin , Lucht Brett L.
Published: December 2020

Lithium titanate (L4Ti5O12 or LTO) is a sought-after alternative in conjunction with high voltage capable cathodes to the graphite anode in lithium ion batteries for electric vehicle and stationary storage applications. LTO offers improved abuse tolerance due to elimination of lithium dendrite formation when compared to graphite, the zero-strain property which enables operation at high rates, wide operating temperature range, and long cycle life.1 The limitations of LTO include a low specific capacity that of which is half the capacity of graphite anode, significant gas generation, and a high working potential (1.55V vs Li0 /Li+). LTO pairing with various Li[NixMnyCo1-xy]O2 (NMC) materials appears interesting as it may offer improvements to the low specific capacity of the LTO material, when compared to cathode materials such as LMO or LCO2 without the complexities and numerous challenges still associated with spinel cathode materials. Herein we report on an electrolyte optimization study for the LiNi0.6Mn0.2Co0.2O2 (NCM622)//LTO electrode couple using multi-layer pouch cells, which focuses on ethylene carbonate (EC) free formulations, with the aim of reducing the amount of gas formed by the LTO anodes.

References

N. Takami, H. Inagaki, Y. Tatebayashi, H. Saruwatari, K. Honda, S. Egusa, J. Power Sources, 244, 469-475 (2013).

N. Gauthier, C. Courrèges, J. Demeaux, C. Tessier, H. Martinez, J. Electrochem. Soc.,
167, 040504 (2020).
Designing a Li-Metal Battery That Survives Practical Operating Conditions
Authors: Park Seongjin , Sun Yang-Kook
Published: December 2020

Rechargeable Li-metal batteries using LiNixCoyMn1-x-yO2 cathode (Li/NCM battery) have a great consideration as the most promising candidates for future high-energy batteries. Despite recent efforts, development of practical Li/NCM battery remains a enormous challenge due to the limited understanding of where efficiency improvements can be made. Herein, we propose the new customizing approach to realizing the practical Li/NCM battery. We suggest the novel methodology to maximize the Li-metal stability by forming a stable solid electrolyte (SEI) layer through in-situ and ex-situ route. The electrolyte comprises 1M LiPF6 and 0.05M lithium difluoro(oxalate)borate (LiDFOB) dissolved in the mixture of ethyl methyl carbonate (EMC) and fluoroethylene carbonate (FEC) solution induced robust and ion conductive inorganic-organic combination such as LiF, Li2CO3, and cross-linked oligomeric borate in SEI layer via in-situ electrochemical reaction. In addition, LiNO3 treatment on Li-metal anode induce Li2O-rich SEI layer via ex-situ route, providing the mechanical strength to maintain the SEI layer from breakdown against to dendritic Li growth at high current density. Finally, the rupture and pulverization issues of commercial Li[Ni0.6Co0.2Mn0.2]O2 cathode in practical loading of LMBs are surmounted by benchmarking a 2mol % Al-doped Ni-rich (Li[Ni0.73Co0.10Mn0.15Al0.02]O2) full concentration gradient (Al2-FCG75) cathode. As a result, the Li/CNM battery based on stabilized Li-metal anode with suitable electrolyte solution and Al2-FCG75 cathode delivers high areal capacity of 4.1 mAh cm-2 and the best cycling stability over 300 cycles at an extremely high current density of 3.6 mA cm-2 in reported LMBs to date.

Reference

S.-J. Park, J.-Y. Hwang, C. S. Yoon, H.-G. Jung andY.-K. Sun, ACS Appl. Mater. Interfaces
2018, 10, 17985.

S. H. Lee, J.-Y. Hwang, S.-J. Park, G.-T. Park and Y.-K. Sun, Adv. Funct. Mater.
2019, 29, 1902496.

S. H. Lee, J.-Y. Hwang, J. Ming, Z. Cao, H. A. Nguyen, H.-G. Jung, J. Kim and Y.-K. Sun, Adv. Energy Mater.
2020, 2000567
Advanced Fluorinated Electrolytes Supporting High-Energy Lithium Batteries with Ni-Rich Cathodes
Authors: Deng Tao , Fan Xiulin , Wang Chunsheng
Published: December 2020

Developing new electrolytes that cater to the needs of lithium anode and Ni-rich cathodes is critical for next-generation battery technologies with high energy density and enhanced safety. Although significant advances have been made in non-aqueous electrolytes with wide electrochemical stability window (ESW), the performance of lithium battery is still not comparable to that of commercial Li-ion batteries (LIBs) due to the notorious reactivity of metallic lithium as well as the catalytic nature of high-voltage cathode. Such situations require rational design of advanced electrolytes and mechanistic understanding on interphase formation for stabilizing the electrolyte-electrode interfaces and supporting the next-generation battery chemistries beyond LIB technology.

In the presentation, I will introduce the design and development of nonflammable fluorinated electrolytes (NFEs) in Prof. Chunsheng Wang group. We demonstrated that the NFEs with wide ESW are able to form thin fluorinated interphase on both Li anode and high-voltage Ni-rich cathodes, thus leading to high efficiencies of Li-metal plating/stripping (> 99.2%) for a 5 V cathode LiCoPO4 (~99.81%) and a Ni-rich LiNi0.8Mn0.1Co0.1O2 cathode (~99.93%).[1] Meanwhile, the NFEs with LiDFOB additive enables high-energy cobalt-free LiNiO2 (LNO) cathode to achieve a good cycle life.[2] The in-situ-formed F, B-rich interphase is proved to protect the LNO from continuous reactions with electrolyte and suppress the structural transformation from layered to disordered rock-salt (NiO) phase. Further study found that the non-polar fluorinated solvent could help maintain the high Li-ion conductivity of NFEs even under -125 oC, thus enable good cycling of all-temperature Li metal batteries operating from -80 to +70 oC.[3] The key findings on NFEs system provide a new avenue towards high-energy and safe Li metal batteries with wide operational temperature range.

References:

[1] X. Fan, L. Chen, O. Borodin, X. Ji, J. Chen, S. Hou, T. Deng, J. Zheng, C. Yang, S. Liou, K. Amine, K. Xu, C. Wang,
Nat.

Nanotechnol.
, (2018) 1.

[2] T. Deng, X. Fan, L. Cao, J. Chen, S. Hou, X. Ji, L. Chen, S. Li, X. Zhou, E. Hu, D. Su, X. Yang, C. Wang,
Joule
, 3 (2019) 2550.

[3] X. Fan, X. Ji, L. Chen, J. Chen, T. Deng, F. Han, J. Yue, N. Piao, R. Wang, X. Zhou, X. Xiao, L. Chen, C. Wang,
Nat. Energy
, 4 (2019) 882.
Composite Paam-Based Hydrogel Electrolyte for Hybrid Aqueous (Zn-Li-ion) Battery
Authors: Zhanadilov Orynbay , Beisbayeva Zhanna , Amze Magzhan , Bakenov Zhumabay , Mentbayeva Almagul
Published: December 2020

Hybrid aqueous rechargeable batteries are very attractive alternative to conventional rechargeable lithium ion batteries for stationary application because of production and usage safety, reduced production cost and environmental friendliness. Previously aqueous rechargeable batteries with Zn/LiCl-ZnCl2/LiFePO4 system with liquid electrolyte has been reported [1]. The system performed a high rate capability up to 60 C with the average operation voltage 1.2 V and cycling performance with a capacity retention of 80 % over 400 cycles at 6 C.

However, there are several drawbacks including water decomposition and zinc dendrite formation hindering the commercialization [1]. The present study aimed to develop a PAAm-based hydrogel electrolyte with inclusion of montmorillonite and halloysite clay nanoparticles for hybrid aqueous rechargeable zinc/lithium ion batteries to overcome above mentioned problems. Polyacrylamide hydrogel was chosen because of its high ionic conductivity, high water content and simple fabrication method in which cross-linking degree, thickness, etc. were optimized. Inclusion of clay could improve mechanical stability of hydrogel electrolyte, prevent water decomposition and dendrite formation.

All tests performed in Zn/LiFePO4 cell operating in an optimized LiCl/ZnCl2 aqueous electrolyte based hydrogel.

Acknowledgement

This research was supported by Faculty-development competitive research grant “Development of safe and high performance flexible Li-ion batteries” #110119DF4514 from Nazarbayev University.

References

N.Yesbolati, N.Umirov, A.Koishybay, M.Omarova, I.Kurmanbayeva, Y.Zhang,

Y.Zhao, Z.Bakenov. Electrochimica Acta, 152 (2015), 505–511.
Effect of KOH Concentration on Mn(III) Dissolution in Rechargeable γ- MnO2 Cathodes
Authors: Kolhekar Snehal , Banerjee Sanjoy
Published: December 2020

The low cost, high theoretical specific capacity (617 mAh g-1) and environmentally benign nature of MnO2 makes it a very attractive material for a host of electrical energy storage applications such as aqueous based Zn/MnO2 batteries or non-aqueous Li/MnO2 batteries and even supercapacitors. Realizing higher energy and power densities in γ- MnO2 cathodes is of crucial interest for both primary as well as secondary battery applications. But achieving a long lasting high energy density rechargeable MnO2 battery suffers from many setbacks. Prime among these setbacks is the inability of γ- MnO2 polymorph to retain its structural integrity when cycled to deeper depths of discharge (DOD). The most widely used model for γ- MnO2 discharge consists of a solid state proton-electron intercalation process upto the 1st electron forming MnOOH and a dissolution-precipitation process during the 2nd electron discharge forming Mn(OH)2. In this paper, we investigate the cycle life degradation mechanism of the γ- MnO2 polymorph in alkaline environment in the 1st electron region of discharge. We conduct three-electrode experiments on 80 wt. % loading γ- MnO2 cathodes to determine the failure mechanism in various KOH concentrations and at various depths of discharge. At 50 % DOD of the 1st electron, we find a significant effect of KOH concentration with upto 70 % retention of discharge capacity over 100 charge-discharge cycles in 10 wt. % KOH compared to only 20 cycles in 37 wt. % KOH. At 40 % DOD of the 1st electron of MnO2, we observe an astounding 177 % improvement in cycle life in 10 wt. % KOH in comparison to poor recyclability observed in 37 % KOH. Post mortem X-ray diffraction analysis revealed the presence of birnessite, δ- MnO2, in the cathode with nanoflower, nanosheet and nanowire morphologies of birnessite observed in 37 wt. %, 25 wt. % and 10 wt. % KOH respectively. To probe into the failure mechanism we conducted four-electrode Pt- wire experiments to detect Mn (III) soluble species during discharge, in-situ. The experiments indicate significant influence of KOH concentration with Mn(III) dissolution, as determined by the presence of δ-MnO2 deposited on the Pt wire, being detected in 37 wt. % KOH at just ~34 % DOD during the 1st electron discharge. We propose, in this paper, that the capacity fade of γ- MnO2 at high DOD of 1st electron is critically related to the amount of birnessite, which is formed during the charging of Mn (III) ions. Since birnessite discharges at a much lower potential than cycled to in our experiments, its contribution to discharge capacity in the 1st electron region of γ- MnO2 is negligible and hence, builds up as an inactive phase, ultimately resulting in capacity fade.

Figure 1
Application of Artificial Interphase on Highly Active NCM811 Cathode Materials
Authors: Chang Yu-Hsiu , Chang Chao-Peng , Yu Ching-Hao , Wu Hung-Chun , Wu Nae-Lih (Nick)
Published: December 2020

The Ni-rich LiNi0.8Co0.1Mn0.1O2 layered oxide (NCM811) is a kind of high-capacity cathode materials for rechargeable Li-ion batteries. However, due to the high Ni content, NCM811 becomes very active and unstable, especially under high temperature environment. This is the reason why NCM811 cathodes often suffer from electrolyte decomposition and then generate a SEI layer on the surface during charge-discharge cycling.

To solve the unstable problems of NCM811, this work is to construct a layer of fluorinated soft artificial interphase on the surface of the NCM811 electrode material by means of simple and convenient polymer-coating and partial-thermal-treatment. When the surface becomes more hydrophobic, the less moisture in the air will adsorb, and it avoids the detrimental reaction with the electrolyte. Also, the coating reacts to some extent with the residue lithium to form lithium fluoride and stabilizes the surface. Electron-conductive additive was added as electron channel to enhance the overall performance of intercalation/deintercalation. The results demonstrate that the artificial surface layer led to substantial improvement in cycle stability.

(This work is supported by Industrial Technology Research Institute, Taiwan.)
(A04 Best Poster Award Winner) Formation Mechanism and Stability of Solid Electrolyte Interphases in Linear Carbonate-Based Electrolytes
Authors: Ebrahiminia Mahsa , Wang Cun , Bedrov Dmitry
Published: December 2020

Broad application of lithium batteries, necessitates improvements in their safety, cycle life, durability and energy density. Clear understanding of the electrode/electrolyte interfaces is one of the important factors in designing batteries with enhanced performance. Linear organic solvents are extensively used in electrolytes of lithium batteries to reduce viscosity and melting temperature of cyclic carbonates. However, these organic compounds are not stable in contact with anode, leading to decomposition of the electrolyte and formation of Solid Electrolyte Interphase (SEI). Although SEI is proven to be one of the most important parts of batteries, its structural complexity, mechanism of formation, and properties are not completely understood yet. In this work, we consider mechanism of formation and stability of SEIs composed of redox products of linear carbonate solvents. So far, the main focus of research was on decomposition products of cyclic carbonates. In case of linear carbonates, the SEI stability consideration is limited to the systems being in DMC solvent and to the best of our knowledge, there are no theoretical investigations on linear carbonate-based SEIs formation mechanism and properties.

In this work, we study Lithium Methyl Carbonate (LMC), Lithium Ethyl Carbonate (LEC) and Lithium Propyl Carbonate (LPC), which are single-electron reduction products of carbonate solvents in contact with the electrode, in their corresponding solvents being Dilithium Methyl Carbonate (DMC), Dilithium Ethyl Carbonate (DEC) and Dilithium Propyl Carbonate (DPC), respectively (Figure 1). Our aim is to chemically, kinetically, and thermodynamically study the aggregation, formation and stability of SEI layer in these systems from experimental, Molecular Dynamics (MD) simulation and Density Functional Theory (DFT) calculation points of view. Our study indicates that in LMC/DMC mixture LMC molecules have strong tendency to self-assemble and have low barriers to undergo second-electron reduction to form stable Li2CO3. Stable SEI was also observed in LPC/DPC as well, which is believed to be a result of slow dynamics of larger molecules and therefore increased possibility of the second-electron reduction near electrode surface. In the LEC/DEC system, however, we did not observe a stable SEI formation due to low tendency of LEC molecules to self-assemble, low electronic affinity coupled with high energy barrier for possible second electron reduction reaction. Therefore, our work illustrates that the selection of the linear carbonate as a blending partner for cyclic carbonates, might have an important impact on the ability of electrolyte to form stable and compact SEI layer.

Figure 1
Potential Dependent Ion Arrangement Near the Electrode/Electrolyte Interface
Authors: Mars Julian Emanuel , Steinrück Hans-Georg , Cao Chuntian , Borodin Oleg , Toney Michael F
Published: December 2020

The electric double layer (EDL) is the ion arrangement evolving at electrolyte interfaces. Despite its importance in many applications such as super-capacitors, lithium ion batteries (LIB), water purification, and stabilization of nanoparticles in solution, the structural motifs of the EDL are still under debate.

In LIB, the molecular scale ion arrangement near the interface or EDL controls solvation and hence mass/charge transfer across the interface. Additionally, the interfacial speciation governs the reductive and oxidative processes at the interface. Thus, it has a great impact on the stability of the electrolyte. Hence, the near-interface structure plays a vital role in the solid electrolyte interphase (SEI) formation which is still poorly understood. The SEI protects the electrolyte from further decomposition and its stability, low electrical conductance, and good Li-ion transport properties are crucial for the cycling ability and long-term stability of the cell. Therefore, an atomic level elucidation of the electrolyte/electrode interface and its rearrangement dynamics due to potential changes is of utmost importance for understanding the behaviors of LIBs, and will ultimately lead to the minimization of ion transport resistance and improved long-term stability.

We present an in-situ X-ray reflectivity (XR) study on the single crystalline boron-doped diamond – electrolyte interface. The metal-like electric conductivity and wide electrochemical window of the single crystalline boron-doped diamond allow us to apply a potential across the interface. We obtain structural information by modeling the potential dependent EDL to reproduce our experimental data. First proof-of-concept results on 1m CsCl(aq) show a clear trend of the XR profile on the applied potential of -1.2V – 1.2V vs AgCl. The length scale of π/qz = 4Å of the observed minima at qz = 0.75 Å−1 corresponds well to the expected length-scale of the inner-Helmholtz layer of the EDL. Our analysis suggests that the population of the inner-Helmholtz layer decreases with increasing potential.

Our efforts allow to challenge the current theoretical models and simulations and will ultimately help to understand the mechanisms involved in the SEI formation and lead to the minimization of ion transport resistance as well as to an improvement of the LIB cycling ability.

Figure 1