bluuebunny/crossref_metadata_2025 huggingface dataset:
The High Performance Silicon Anodes Including New Water Based Binder in Lithium Ion Batteries
Authors: Kim Soo Jung , Kim Nam Seon , Han Sang Wook , Choi Kwang Shik
Published: February 2020

Silicon based negative active material has very high charge capacity and is widely applied to a high capacity battery.

However, the silicon based negative active material may expand by about 300% to about 400% during charge and discharge.

Recently much attention has been devoted developing functional binders that can improve adhesion on silicon particle and accommodate substantial volume change during the charge/discharge process to maintain the electrode structure.

The binders for silicon electrodes hold stiff polymeric backbones as like carboxymethyl cellulose (CMC), poly(acrylic acid), and alginate show better electrochemical performance than commercial binders.

Despite promising progress, the current research on polymer binders for silicon is still far from the practical application where high mass loading is necessary for the high areal capacity.

Here we report high performance silicon anodes using new water based binder including inorganic binder.

This polymer matrix is compatible with lithium ion slurry manufacturing process, and can maintain both electric conductivity and mechanical integrity during the battery operation which results in good stability, rate capability, and cycle-life characteristics at high mass loading (>4.5 mg/cm2).
Novel Nanostructured Materials for Metal-Air Batteries
Authors: Liu Zhaolin
Published: February 2020

This talk will focus on the design and synthesis of nanostructured non-precious metal-based hybrid catalysts for metal-air batteries. The presentation will describe some our works in nanostructured hybrid bifunctional electrocatalysts as air electrode for Zn-air rechargeable batteries, as well as nanostructured porous perovskite and spinel metal oxide catalytic materials as air electrode for Li-air batteries.

In this presentation, I will introduce the fundamental and the most recent and significant scientific progresses made in the fields relevant to Zn-air and Li-air batteries, with emphasis placed on air electrodes. The preparation of MnO2 nanotubes functionalized with Co3O4 nanoparticles and their use as bifunctional air cathode catalysts for oxygen reduction reaction and oxygen evolution reaction in rechargeable zinc-air batteries will be reported. These hybrid MnO2/Co3O4 nanomaterials exhibit enhanced catalytic reactivity toward oxygen evolution reaction in alkaline conditions compared with that in the presence of MnO2 nanotubes or Co3O4 nanoparticles alone. Other bifunctional catalysts for oxygen reduction and evolution reactions in Zn-air batteries include spinel MnCo2O4/ nanocarbon hybrids, perovskite lanthanum cobalt manganese oxides/nanocarbon hybrids (LCMO/NC), Co3O4 nanoparticles decorated carbon nanofiber and cobalt sulphide/N- or S-doped grapheme etc. I also will report porous cobalt-manganese oxide nanocubes derived from metal organic frameworks and porous perovskite LaNiO3 nanocubes as cathode catalysts for rechargeable Li-O2 batteries.
Lithium-Sulfur Batteries: High Loading Cathode, New Electrolyte and Non-Lithium Metal Anode
Authors: Lu Dongping , Xiao Jie , Li Qiuyan , Ferrara Seth A , Shao Yuyan , Graff Gordon L , Liu Jun , Zhang Ji-Guang
Published: February 2020

Lithium sulfur battery (Li-S) has attracted intensive interest in recent years due to its high specific capacity, low cost, and abundant resources of sulfur. Theoretically, a high specific capacity of 1675 mAh g-1 and a specific energy of 2567 Wh kg-1 are expected for sulfur cathode. Practically, the energy density of Li-S battery is projected to be two to three times higher than that of state-of-the-art Li-ion batteries (180 Wh kg-1). However, the commercial applications of Li-S batteries are still hindered by several challenges.2  One is that with elevated sulfur loading above 3 mg/cm2, which is essential for high energy applications, new problems occur including the cathode cracking, electrode wetting and low sulfur utilization rate. The second and more detrimental issue that limits Li-S cell performance is interfacial stability and cycling reversibility of lithium metal anode, which easily reacts with both electrolyte solvents and the formed polysulfides during battery cycling and leads to unavoidable shuttle and continuous consumption of active sulfur species. These side reactions are significantly exacerbated under conditions of coupling with high-areal loading sulfur cathode and/or cycled at elevated current densities. As a result, thick and porous interface will be quickly built up on lithium anode and leads to quick impedance increase and thus fast capacity decay of the battery.3 The third problem is the amount of electrolyte required for full dissolution of the polysulfides. The dissolved polysulfides cause endless shuttle and continuous Li anode corrosion due to the lack of effective solid electrolyte interface (SEI) on lithium. In addition, the large amount of electrolyte significantly lowers the energy density of the battery, which is undesired for high-efficient portable devices or electric vehicle energy storage applications

     To overcome the aforementioned hurdles in Li-S batteries, multiple approaches have been proposed and successfully demonstrated by our group, spanning from sulfur cathode, anode and electrolyte.  At the meeting, we will present our recent progresses on the Li-S battery system including the rational design of carbon/sulfur composite for large area and high loading sulfur cathode preparation, alternative non-Li anode materials for Li-ion sulfur batteries, and development of new electrolyte.

References

 1.          Ji X, Lee KT, Nazar LF. A highly ordered nanostructured carbon-sulphur cathode for lithium-sulphur batteries. Nat Mater 2009, 8(6): 500-506.

 2.           Lv D, Zheng J, Li Q, Xie X, Ferrara S, Nie Z, et al. High Energy Density Lithium–Sulfur Batteries: Challenges of Thick Sulfur Cathodes. Advanced Energy Materials 2015, 5,1402290.

 3.          Lv D, Shao Y, Lozano T, Bennett WD, Graff GL, Polzin B, et al. Failure Mechanism for Fast-Charged Lithium Metal Batteries with Liquid Electrolytes. Advanced Energy Materials 2015, 5,1400993.
Ladder-Inspired SnO-Multiwalled Carbon Nanotubes with Sulfur Impregnation as Robust Cathode Material for High-Rate Lithium-Sulfur Batteries
Authors: Kim A-Young , Kim Min Kyu , Kim Ji Young , Jin Ik-Kyu , Wen Yuren , Gu Lin , Choi Ho-Suk , Byun Dongjin , Lee Joong Kee
Published: February 2020

Lithium-sulfur (Li-S) battery has the theoretical potential to surpass lithium-ion batteries in terms of capacity and energy density for applications in electric vehicles and hybrid electric vehicles. However several drawbacks prevent it from practical application, such as (1) the low electrical conductivity of both sulfur (5 × 10–3 S cm–1), (2) the large volume expansion (about 80%) during lithiation, (3) the intermediate lithium polysulfides (Li2Sx, 3 ≤ x ≤ 8). During the cycling process, the soluble lithium polysulfides may migrate to the anode side by the “shuttle effect”, resulting in significant irreversible capacity loss and corrosion on the lithium metal anode [1]. Many strategies have been developed to enhance the conductivity of sulfur and suppress the dissolution of polysulfides. The carbon host materials used in Li-S cathodes, despite their excellent electrical and mechanical performances, still demonstrate drawbacks such as rapid capacity fading under cycling and reduced entrapment of polysulfide, leading to decreased rate capability [2]. Therefore, a hybrid design is required for a robust cathode material with high conductivity and low volume change during lithiation-delithiation process.

Here, we present ladder-inspired multi-walled carbon nanotubes (MWCNT) filled with tin monoxide (SnO) nanoparticles as a new host material. The MWCNT-SnO/S electrode exhibited excellent electrochemical performance such as stable cycling performance and high rate capability. In situ transmission electron microscopy results indicate that the ladder-inspired MWCNT-SnO host efficiently suppresses volume expansion during lithiation and reduces polysulfide dissolution. Furthermore, the ordered SnO nanoparticles facilitate fast electron and ion transfers during the redox reactions, due to act as connecting links between the walls of MWCNT. This development approach can also be applied to other energy storage devices, including lithium-ion batteries and hybrid supercapacitors.

References

[1] H. Yamin, A. Gorenshtein, J. Penciner, Y. Sternberg, E. Peled, J. Electrochem. Soc. 135 (1988) 1045-1048.

[2] Y. Yang, G. Y. Zheng, Y. Cui, Chem. Soc. Rev. 42 (2013) 3018-3032.
Ultrafast Charging & Superb Cycle Life Battery Technology Leads to EV Consumer Satisfaction
Authors: Mattis Wenjuan Liu
Published: February 2020

Li-ion batteries are one of the most potential candidates as the energy storage devices mainly due to their high energy densities with fairly good rate capabilities and a fairly long cycle life. This technology both drives and is driven by applications, from small sized mobile devices of information technology to large-scale electric vehicles (xEVs) and energy storage systems (ESSs).  Each application target has its own specification so that electrode materials should be chosen to meet requirements of the corresponding application. In this presentation, I will introduce Microvast Inc's ultrafast charging & superb cycle life battery technology which leads to EV consumer satisfaction. Microvast has developed a roadmap to the electrified future we all hope to see.
Inert Atmospheric Analysis Method for ESS Recycling of Waste Lithium Ion Batteries from Electric Vehicle
Authors: Nam Sang Cheol , Seo Inseok , Kim Byoung Ju , You Seungjea , Kang Sung
Published: February 2020

It is expected that waste LIB(lithium ion batteries) more than 1 million pieces will spill out of xEV from 2020, and various researches for recycling are under progress in world wide. Currently, recovery of valuable metal and high purification is conducting by disassembling and chemical decomposition of batteries. Recently there is motion to reuse waste LIB to ESS(Energy Storage System) considering economical value of CO2 reduction effects. To do this, a series of gathering, disassembling, analyzing, re-treatment, grading and reprocessing process of waste LIB have to be managed synthetically. Among them, chemical analysis of waste LIB using inert atmospheric condition is important to clarify degradation mechanism of lithium ion batteries. In this study, we fabricated the full cell with structure of LCO/EC:DEC in 1M LiPF6/graphite, and the surface characterization of SEI layer formed on LCO and graphite surface after charge/discharge test was analyzed under inert atmospheric conditions using XPS and AES techniques.The degradation mechanisms by change of SEI layer with cycling and surface characterization of different active materials will be discussed.
Lithium ion Batteries-supercapacitor Hybrid
Authors: Caban-Huertas Zahilia , Dubal Deepak P. , Gómez-Romero Pedro
Published: February 2020

Since their introduction, lithium ion batteries (LIBs) have become ubiquitous for powering portable electronic devices. However, the charging rate of graphite (by far the most common anode material) is limited by lithium diffusion into the material.

A critical issue of LIBs technology is the low theoretical specific capacity of conventional graphite anodes, limited to 372 mAh/g1. For this reason, a large fraction of current research is focusing on alternative anode materials

Thus, surface engineering of carbon particles (active material design) and modification of carbon electrode structure (electrode design) are necessary to alleviate these critical limiting factors. Herein, we are providing a novel synthetic approach to obtain N-doped carbon nanotubes (N-CNTs) starting from the synthesis of polypyrrole nanotubes (PPy-NTs) followed by pyrolysis. This approach leads to materials and electrodes with the highly porous nature of PPy-NTs and great graphitic texture with copious heteroatom functionalities2.

The N-CNTs were used as the negative electrode coupled with a positive C-LFP (C-coated LiFePO4) with a fractal granularity, prepared in our lab through an eco-friendly water-based synthesis, resulting in a hybrid device with good electrochemical properties.

References

1.            Scrosati, B. & Garche, J. Lithium batteries: Status, prospects and future. Journal of Power Sources
195, 2419-2430 (2010).

2.            Dubal, D.P. et al. Synthetic approach from polypyrrole nanotubes to nitrogen doped pyrolyzed carbon nanotubes for asymmetric supercapacitors. Journal of Power Sources
308, 158-165 (2016).
Using Computer Simulations to Understand and Predict the Properties of Paradigmatic Lithium-Ion Storage Materials
Authors: Otero Manuel , Urquiza Laura , Chauque Susana , Gavilan Maximiliano , Perassi Eduardo , Velez Patricio , Oviedo Oscar Alejandro , Cámara Osvaldo Raúl , Luque Guillermina , Oliva Fabiana Yolanda , Barraco Daniel E , Franco Alejandro A. , Leiva Ezequiel Pedro Marcos
Published: February 2020

In terms of sustainable development and environmental issues, the use of efficient storage systems is an increasingly critical point. The world has undergone a great technological revolution in the past 20 years led by lithium ion batteries, due to their high energy density. However, in order to meet the energy demand of our modern life, a new generation of lithium batteries, more powerful, efficient and cheaper, is desirable. Depending on the problem to be addressed, it is useful to model the system at different scales. For example, while first-principles calculations may be useful to predict equilibrium potentials, semiempirical potentials along with molecular dynamics or Monte Carlo simulations may be applied to understand collective phenomena.  In the present work we show in
terms accessible to experimentalists 
how the use of different simulations tools may be helpful to analyze different aspects of lithium storage materials. The topics to be addressed in the present work are:

Use of first- principles calculations to optimize the stability of Si-Graphite nanostructures.

Application of Monte Carlo simulations to get thermodynamic information on the storage of Li ions into graphite.

Optimization of composites using coarse-grained models.
Porous Si/C Composite Anode Materials for Lithium Ion Batteries
Authors: Fan Li-Zhen , Wang Mingshan
Published: February 2020

Among all the anode materials, silicon is one of the most attractive anode materials for lithium-ion batteries because of its highest capacity of 4200 mAh g-1, satisfactory voltage window for lithium insertion and extraction (<0.5 V vs. Li/Li+), high safety and low cost. However, the practical utilization of Si as anode material is hindered by its huge volume changes (300%) induced by the lithium-ion insertion and extraction processes, culminating in the pulverization of electrode structure as well as the poor cycling performance. In addition, the low electrical conductivity of pristine Si and the difficulty in the formation of stable solid-electrolyte interface (SEI) films have also restrained the commercialization of Si anode material. Here we report a series of silicon based composites [1-10], such as self-supporting grapheme/Si film, three dimensional porous carbon/silicon composites, three dimensional silicon/TiOx/carbon framework, etc, aiming at solving the problems of current silicon anode materials. Those porous silicon based anode materials have demonstrated to be effective in maintaining good electronic contact among particles and accommodating the mechanical stresses experienced by the huge volume change of active silicon associated with Li insertion/extraction processes.

References

[1] M.S. Wang, Y. Song, W.L. Song, L.-Z. Fan*, ChemElectroChem. 1(2014) 2124-2130.

[2] M.S. Wang, L.Z. Fan*, M. Huang, J.H. Li, X.H. Qu, J Power Sources. 219(2012) 29-35.

[3] M.S. Wang, W.L. Song, J. Wang, L.Z.Fan*, Carbon. 82(2015) 337-345.

[4] M.S. Wang, W.L.Song, L.Z.Fan*, J. Mater. Chem. A, 3(2015) 12709-12717.

[5] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Electrochim. Acta, 2013, 89: 394-399.

[6] H.C. Tao, L-Z Fan*, Y.F. Mei, X.H. Qu. Electrochem. Comm., 2011, 13: 1332-1335.

[7] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Solid State Ionics, 2012, 220: 1-6.

[8] H.C. Tao, L.-Z. Fan*, W.-L. Song, M. Wu, X.B. He, X.H. Qu. Nanoscale, 2014, 6 (6): 3138-3142.

[9] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Electrochim. Acta, 2013, 89: 394-399.

[10] H.C. Tao, M. Huang, L.-Z. Fan*, X.H. Qu. Solid State Ionics, 2012, 220: 1-6.

Figure 1
Facile Lithium Ion Transport through Superionic Pathways Formed on the Surface of Li3V2(PO4)3/C for High Power Li-Ion Battery
Authors: Han Dongwook , Eom Ji-Yong , Yun Ju-Ho , Yoo Seung-Eul , Kang Yong-Mook
Published: February 2020

We report a new discovery for enhancing Li ion transport at the surface of Li3V2(PO4)3 particles through superionic pathways built along an ionic conductor. The Li3V1.95Zr0.05(PO4)3/C composite has much higher initial discharge capacity, superior rate-capability, and excellent cycling performance when compared with pristine Li3V2(PO4)3/C. This is partly due to the occupation of vanadium sites by Zr4+ ions in the Li3V2(PO4)3 host crystals and facile Li ion migration through a LiZr2(PO4)3-like secondary phase that forms on the surface of the Li3V1.95Zr0.05(PO4)3 particles. Our ﬁndings about high Li ion transport and structure stabilization induced by Zr incorporation suggests a breakthrough strategy for achieving high-power Li rechargeable batteries using NASICON-structured cathode materials in combination with nanoarchitecture tailoring.

Figure 1
In-Situ Solid State NMR for Characterizing Battery Materials
Authors: Lorie Lopez Jose L. , Co Anne C. , Grandinetti Philip J.
Published: February 2020

The demand for inherently safe, large capacity, high-rate capability energy storage has led to the investigation of a class of metallic and semi-metallic elements that form stable intermetallics with lithium, providing Li+ storage capacities of three to ten times that of today’s lithium-ion batteries.  Unfortunately, such high capacity intermetallic anodes undergo structural transformations from crystalline to amorphous states with large volume expansions upon intercalation, changing the anode's microstructure and local chemical environments, which lead to reduced capacity.  Because of their amorphous nature, the atomic-level structures of the intermetallic are not amenable to study by conventional diffraction techniques.  

Solid-state nuclear magnetic resonance (NMR) spectroscopy is an ideal technique to probe amorphous materials and understand how kinetically driven compositional changes affect the material microstructure and the local chemical environment.  We have measured the 7Li and 119Sn NMR spectra of electrochemically lithiated tin ex-situ and have identified a number of different lithium environments.  Furthermore, we have measured in-situ 7Li NMR spectra as a function of lithiation and de-lithiation of different materials, including graphitic carbon, silicon, and tin.  We will discuss the findings and their implications for the design of various nanostructured intermetallic anodes.
Comparative Study on the Electrochemical Performances of SiO Anode Materials with Carbon-Coating and Boron-Doping for Lithium-Ion Batteries
Authors: Baek Seong-Ho , Woo Jihoon , Kim Jae Hyun
Published: February 2020

Recently, Silicon monoxide (SiO) has been received much attention as an alternative choice instead of pure Si anode materials. When SiO anode undergoes lithiation processes, Li oxide (Li2O) and Li silicates (Li4SiO4) are mainly formed and that act as a more stable phase than the Li-Si alloys during long cycles. Moreover SiO is thermodynamically unstable at all temperatures, it can be easily transformed into nano-crystalline Si (nc-Si) and SiOx during heat treatment, triggering a disproportionation reaction. The nc-Si acts to increase the reversible capacity and the SiOx matrix plays an important role in accommodating the volume expansion of embedded nc-Si during alloying/de-alloying processes. However, the electrical conductivity of heat-treated SiO remains low because of this material’s intrinsic semiconductor nature and inactive phases. Carbon coating has been regarded as one of the most effective and typical ways to improve the electrochemical properties of SiOx. Dispersed carbon particles provide pathways for electron transfer and decrease the resistance of the electrode, thus resulting in improved conductivity and electrochemical properties of the SiO negative electrode. However, the local capacity fading caused by electrical loss between the active materials and the carbon coating is unavoidable during long cycle test. Moreover, carbon coating requires additional processing with carbon sources. In this study, we introduce a comparative study that consists of boron-doped SiO (HB-SiO) and carbon-coated SiO (HC-SiO) to verify the effective way for improving the electrochemical performances of SiO anode materials. From the electrochemical results, HB-SiO electrode exhibits about 1.6 times higher than that of HC-SiO electrode, having 611 mAh g-1 at 0.5 C rate after 500 cycles. Electrochemical impedance spectroscopy (EIS) measurement reveals that the internal resistance of the HB-SiO electrode is superior to that of HC-SiO electrode.
Cycle Stability of Silicon Nanoparticles Coated with Nitrogen-Doped Carbon Layer for Lithium Ion Battery Anode
Authors: Cho chae Ryong , Choi hun Seok , Pham-Cong De , Cho Jin Hyuk
Published: February 2020

Silicon is one of the promising candidate materials for lithium ion anode. This anode has a theoretical specific capacity of 4200 mAh/g which is about 10 times higher than the commercial graphite anode. However, Si anode has a short cycle life during the lithiation-delithiation process because of its volume expansion of up to 400%. In this study, to improve the cycle stability of Si anode through the control of volume expansion, we fabricated the single crystal Si nanoparticles (dia. ~50 nm) by using laser photo-pyrolysis technique and then the nitrogen-doped carbon layer was coated on them by using FeCl3 source. The electrochemical performance of samples according to the amount of FeCl3(0.3-2g) was investigated. The capacity retention of the Si nanoparticle with N-doped carbon layer (Si@NC) sample was approximately 74.9% at 1C after 300 cycles. Surface chemical states for elements of the anode materials according to the thickness of nitrogen-dpoed carbon layer are mentioned in detail. The effect of the coating layer is very strong to prevent Si volume change, so our experimental result for cycling test could be expected.
Surface Modifications of LiFePO4 Electrode for Aqueous Lithium Ion Batteries
Authors: Tron Artur V. , Kim Jaemin , Ryu Ji Heon , Choi Wonchang , Mun Junyoung
Published: February 2020

1. Introduction

The rechargeable lithium-ion batteries (LIBs) with organic electrolytes have become the alternative energy supply for portable equipments, consumer electronic devices and high power applications such as electric vehicles and power storage for renewable energy [1]. However, their safety issue and high cost limit their application for large scale energy storage because LIBs use the flammable and expensive organic electrolytes. An aqueous rechargeable lithium battery (ARLB) was first reported by Dahn et al., which has advantages such as safety and low cost [2]. However, its practical application was hindered due to its poor cycling and not good rate capability. Here, we have shown that surface modifications of LiFePO4 showed a much better rate capability in aqueous electrolyte than pristine LiFePO4.

2. Results and discussion

The influence of the surface coating on the electrochemical properties of LiFePO4 cathode in aqueous electrolyte solution was investigated by systematic electrochemical and instrumental analyses. The electrochemical performance of pristine LiFePO4 and coated LiFePO4 is presented in Fig. 1. Despite the high ionic conductivity of the aqueous electrolyte (1 M Li2SO4 in water), the pristine LiFePO4 did not show the high rate capabilities. In detail, the pristine LiFePO4 and coated LiFePO4 in aqueous electrolyte, which can deliver the initial discharge capacity of 127.5 and 132.1 mAh g−1 at 1 C, respectively. The pristine LiFePO4 and coated LiFePO4 have still the discharge capacity of 108.9 and 122.7 mAh g−1 after 100 cycles. Based on these results, it is confirmed that the resistance from the surface failure mode of LiFePO4 could be a main hurdle for cycle decaying especially in the aqueous electrolyte. After the surface modification of the electrochemically stable inorganic species, the rate capability and the cycle life are further improved. This coating enhance the surface stability to the aqueous solution and presents very promising cycle and rate capabilities for the development of ARLBs. Furthermore, they are investigated in detail by using XPS, SEM and TEM analyses.

Acknowledgments

This research was supported by the Post-Doctor Research Program (2014-2015) through the Incheon National University (INU) and the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning (NRF-2014R1A1A1038248).

Reference

[1] M.R. Palacin, Recent advances in rechargeable battery materials: a chemist’s perspective, Chem. Soc. Rev. 38 (2009) 2565-2575.

[2] W. Li, J.R. Dahn, D.S. Wainwright, Rechargeable Lithium Batteries with Aqueous Electrolytes, Science 264 (1994) 1115-1118.

Fig. 1. The cycling performance of pristine LiFePO4 and coated LiFePO4 in aqueous solution.

Figure 1
Following Synthesis and Structure of Spinel and Layered Compounds Using Neutron Powder Diffraction
Authors: Huq Ashfia
Published: February 2020

Sensitivity to light elements in the presence of heavier elements makes neutron diffraction an ideal tool to study oxides, hydrides and compounds containing Li.  As a result neutron crystallography has been very successfully used to elucidate structures of electrode and electrolyte materials used in Li-ion battery materials.  In this presentation, I will speak about several of these electrode systems where structure helped understand the electrochemical properties and synthesis mechanism.
Structural and Chemical Characterization of Li-Ion Batteries
Authors: Romano Linda , Neuburger Monica , Tsung Lancy , Schneider Yanika , Pajcini Vasil , Robie Steve , Wang Xinwei
Published: February 2020

Lithium ion batteries have improved rapidly in the last 10 years to become the main power source in portable electronics, telecommunications, and large capacity applications such as in electric vehicles (EV). Ongoing improvements in characterization techniques must also meet industry, regulatory and consumer needs as battery manufacturers and end-users demand higher battery efficiencies, lower cost, and most importantly, safety. 

At Evans Analytical Group (EAG, Inc.), we provide a suite of techniques suitable for both the structural and chemical analysis of Li-ion batteries. Both scanning and transmission electron microscopy (SEM and TEM) are used to provide the thickness and microstructure of the various layers in the battery. Ion milling techniques are used to preserve the integrity of the sample to assure an accurate representation of the original state of the battery materials. This is essential in order to properly understand process development or battery failures. TEM combined with X-Ray Diffraction (XRD) can also be used to analyze the phase transformations associated with the diffusion of Li-ions. Additionally, the thickness of the thin SEI layer caused by electrode-electrolyte interfacial reactions can only be visualized by TEM.

Degradation mechanisms of the battery materials can be analyzed with surface analysis techniques such as X-ray photoelectron spectroscopy (XPS) to detect chemical state information and gas chromatography (GCMS) techniques to detect volatile components that can lead to swelling of the battery. These techniques along with Raman and infrared spectroscopy (FTIR), and Glow Discharge Mass Spectrometry (GDMS) can detect the organic and inorganic species present in the battery, including any impurities that may be present. GDMS is commonly used for purity certification of cathode materials such as LiCoO2, LiFePO4, and LiCoMnNiOx
.Inductively coupled optical emission techniques (ICP-OES) can be used to determine the Li/metal ratio to within a 1% uncertainty, which is essential for tuning the cycling stability of Li-ion batteries.

In this presentation we will demonstrate the multi-disciplinary approach of using these various techniques and the importance of proper sample preparation for accurate analyses of Li-ion batteries. This approach enhances the value of the information obtained and can accelerate product development.
Investigation on Electrochemical Properties of TiNb6O17 As the New Anode Materials for High Power Lithium Ion Batteries
Authors: Lee Yong Seok , Ryu Kwang Sun
Published: February 2020

Among the commercial anode materials, graphite isn`t suitable for high-power applications such as electric vehicles and large-scale energy storage due to formation of the solid-electrolyte interphase (SEI) leading to lithium irreversibly at about 0.8V and inactive high rate performance. Although, Li4Ti5O12 (LTO) are being pursued as alternatives to graphite electrodes due to high lithium storage voltages (1.0~2.0V) which are higher than the formation of SEI voltage and high rate capability, it has low theoretical capacity (~175mAhg-1). Recently titanium-niobium oxides (TNO) such as TiNb2O7, Ti2Nb10O29 with high redox potential range have been considered as interesting candidates for anode material of LIB. Because they have higher theoretical capacity of 380~396mAhg-1 due to multiple redox couples such as Ti4+/Ti3+, Nb5+/Nb4+, Nb4+/Nb3+ by compared with LTO having only Ti4+/Ti3+ redox couple. In addition, they have good stability, high rate capability. However, they are show limited reversible capacities (240~270mAhg-1) owing to low electronic conductivity and lithium diffusion coefficient. Chunfu Lin et al. presented that TiNb6O17 showed higher capacity, lithium diffusion coefficient and high rate performance than Ti2Nb10O29. Because it is consist of larger amount of Nb5+ ions with larger size (0.64A) than that of Ti4+ ions (0.605A). As a result, it has more open lithium insertion structure and lithium diffusion coefficient than Ti2Nb10O29. But this study not exactly proposed chemical properties such as oxidation state, lithium insertion behavior of TiNb6O17.

Based on above study, we have compared physical properties and electrochemical performance of new compound TiNb6O17 and TiNb2O7 which were fabricated using a solid-state reaction method. In a typical synthesis, TiO2 and Nb2O5 in the molar ratio (1:2, 1:6) were mixed with ethanol in a ball mill at 300rpm for 4h. After drying, calcination treatment is carried at 1100°C for 10h in air atmosphere. The crystal structures were determined by X-ray diffraction (XRD), rietveld refinement in order to compare lattice parameters and unit cell volume. X-ray absorption spectroscopy (XAS) was measured to confirm variation of oxidation state and lithium insertion/extraction behavior after charge and discharge. The morphologies were observed by scanning electron microscope (SEM). Finally, we investigated electrochemical performance by measuring cyclic voltammetry, galvanostatic charge-discharge curve and C-rate. Also, electrochemical impedance spectroscopy (EIS) and slow scan rate cyclic voltammetry (SSCV) were measured to compare lithium diffusion coefficients of TiNb2O7 and TiNb6O17. As the result of, TiNb6O17 exhibited better electrochemical performance with lithium diffusion coefficient, charge-discharge capacities and high rate performance than TiNb2O7.
Electrochemical Characteristics of Silicon/Carbon Anode Composite with Various Binders and Additives
Authors: Lee Jong Dae , Park Ji Yong
Published: February 2020

In recent years, lithium ion battery has been widely used on portable electronic devices and electric/hybrid vehicles because of its high energy density and cycling stability. As an anode material for the lithium ion battery, Silicon(Si) is getting attention for its high theoretical specific capacity (about 4200mAh/g) and its proper potential range for lithium insertion and extraction. However, Si has properties that could be obstacles for its practical use as the lithium ion battery anode. Si not only has low intrinsic electric conductivity but also undergoes severe volume changes during the lithium ion insertion/extraction process which results in pulverization of the electrode materials, causing the capacity to fade. To overcome these problems and enhance the electric conductivity, we synthesized Silicon/Carbon composites as an anode material. Si/C composites were prepared by two step method, including magnesiothermic reduction of SBA-15(Santa Barbara Amorphous material No. 15) and carbonization of phenol resin. The electrochemical performances of Si/Carbon composites were investigated to find the effect of binders and an electrolyte additives by charge/discharge, cyclic voltammetry and impedance tests. The anode electrode of Si/C composite with PAA binder appeared better capacity(1,899 mAh/g) and the capacity retention ratio(92%) than that of other composition coin cells during 40 cycles. Also, Vinylene carbonate(VC) was tested as an electrolyte additive. The influence of this additive on the behavior of Si/Carbon anodes was very positive(3,049 mAh/g), since the VC additive is formed passivation films on Si/C surfaces and suppresses irreversible changes in electrolyte solution .
Simplification in Processing Lithium-Iron-Phosphate-Powders By Design of Secondary Agglomerates
Authors: Pettinger Karl-Heinz
Published: February 2020

Problems of submicron active powders are their big surfaces, such as lithium iron phosphate. Owed to this the coating process requires a lot of solvent. Result is a low solid content, respectively a high slurry viscosity. Therefore special technology and big efforts are necessary for the industrial mass production to process such submicron lithium iron phosphate powders. To overcome the handling difficulties of the submicron powder, spherical secondary agglomerates have been synthesized from those submicron particles. These agglomerates have the size of standard oxide cathode powders (2 µm – 30 µm).

The tap density of the agglomerates could be reduced and the surface area is much lower (~30%). Due to this fact, high solid contents can be realized in the slurry. This leads to reduced amounts of necessary solvent within the coating process. Advantages for the processability are in summary: higher tap density, reduced surface area, reduced solvent demand, greatly simplified slurry dispersing processes and high areal loadings of the electrodes.

The synthesis of secondary agglomerates with lithium iron phosphate allows much better processability and a higher areal loading in the electrodes by preservation of the advantages of the sub-micron materials.

This work compares electrodes of the newly developed lithium iron phosphate secondary agglomerates with the primary submicron particles in respect to their areal loading, high rate capability and processability. Lithium iron phosphate has a very good rate capability and excellent safety features. The submicron powder has disadvantages that lead to a highly increased effort in processing and a limited areal loading. With the design of  spherical agglomerates those disadvantages could be eliminated. Moreover all the advantages of the material itself could be combined with better processability. Processability and the full cell performance of primary particles with those of  secondary agglomerates from lithium iron phosphate are compared.

Electrodes prepared from the secondary agglomerates make it even easier to reach higher areal loading ( >2 mAh/cm²  or 13 g/cm²). Additionally the electrochemical performance of the primary particles could be enhanced. The increased tap density and the smaller surface area enhance processability. Reduced amount of solvent enable slurries with improved rheology for established dispersing and coating processes.

The design of secondary agglomerates leads to much better processable cathode powders and electrodes with retained or improved electrochemical properties of such prepared with the original powder material.

Figure 1
Effects of Adsorbed Water on Nano Silicon for Lithium-Ion Battery
Authors: Yoshida Shuhei , Masuo Yuta , Shibata Daisuke , Haruta Masakazu , Doi Takayuki , Inaba Minoru
Published: February 2020

Silicon has been developed as a promising anode in the next generation lithium-ion batteries due to its high gravimetric capacity density of 3580mAh g−1 at room temperature. However, the lithiation and delithiation reactions are accompanied by large volume changes, resulting in the fracture and pulverization of Si particles and leading to the failure of electrical contacts and poor cycleability. To suppress the physical stress due to its large volume change, we have reported Si Leaf Powder® (Si-LP, Oike & Co., Ltd.), which is amorphous Si nano-flake powder exhibited a good cycleability.1-3 Another serious problem for Si-LP anode such as a large irreversible capacity in the initial and during cycleability remain to be solved for practical use. In previous studies, we have reported Li pre-doping technique using direct contact method with Li foil and Li-naphthalene complex solutions, which completely compensated a initail large irreversible capacity. 4-5Unfortunately, irreversible capacity was continually generated during cycleability and coulombic efficiency was hovered at 97.9 % even after 10 cycle, where part of charging Li was considered to be consumed for the decomposition of electrolyte solution as solid electrolyte interface (SEI).

 In this study, the effects of adsorbed water on nanolized amorphous silicon and its electrodes were investigated by meas of analysis of Karl-Fischer method and in-situgas generation measurement under different drying condition. In addition, their electrochemical properties including the charge and discharge characteristics were carried out to elucidate the effects of containing water.

 1,743 ppm of water in nano-flake amorphous silicon powder were detected at 250°C Karl-Fischer method even after 1 hour drying at 120°C under 3Pa. This result indicated that nano-flake amorphous silicon were strongly bonded with water and the water was not easy to remove in electrode drying process, which were usually conducted around 100°C in practical CMC/SBR binder electrode. In coparision with graphite electrode, more than twenty times of adsorbed water were observed in nano-flake amorphous silicon electrodes and considerred to track inside the cell, leading to low coulombic efficiency not only initial but during cycleability. Actually, H2 gas generation was increased and initial coulombic efficiency was enhanced after dried at 180°C under 3Pa. In addition, remarkable coulombic efficiency improvement of 99.9 % (2140 mAh g−
1) was observed after 10 cycles. The results of this study show that nanoized silicon strongly adsorbed water , which continuously caused the decomposition of electrolyte solution.

References: [1] K. Nakai et al., Electrochemistry, 78 (2010) 438.; [2] M. Saito et al., J. Power Sorces, 196 (2011) 6637.; [3] M. Saito et al., Solid State Ionics, 225 (2012) 506.; [4] T. Okubo et al., Solid State Ionics, 262 (2014) 39.; [5] S. Yoshida et al., Electrochemistry, 83 (2015), 843.
Investigation of Electrochemically Driven Li-Si Phase Formation and Li Diffusion
Authors: Lyons Daniel Joseph , Co Anne C.
Published: February 2020

We have carried out extensive ultra-slow scan cyclic voltammetry on nanoscale silicon to elucidate the electrochemical formation of Li-Si alloys and determine diffusion coefficients. Our results suggest a multi-cycle permanent conversion of bare silicon to the first Li-Si phase, Li12Si7, as the least lithiated state. This constitutes a significant part of the capacity fade observed in silicon electrodes. In addition we observe multiple diffusion constants in long-term current transients using established models from literature.  The electrochemically obtained data will be complemented by a neutron based technique previously developed in our group, referred to as neutron depth profiling, to elucidate the Li distribution and potential trapping or slow kinetics of Li12Si7 within the material resulting in capacity fade.
Redox Activity of Li3VF6 and Similar Compounds at High Voltages
Authors: Plews Michael Rhys , Krakra Jenine , Neto Wanderlino , Aslam Mohammed , Samreen Maseera , Yi Tanghong , Cabana Jordi
Published: February 2020

Increased energy density is required for rechargeable batteries to keep up with the consumer demand for electronic devices, electric vehicles, and smart grids. Current lithium ion battery technology utilizes cathodes with high voltage and capacity against a carbon anode, shuttling Li ions back and forth on charge and discharge in a non-aqueous electrolyte. No new commercially viable cathodes with greater capacity than those identified by Goodenough and co-workers1 have been yet found, with no real increase in capacity over the original LiCoO2 composition since 1980. Options to increase energy density in Li-ion batteries can be summarized by increasing the voltage or lowering the molar mass of the active material in the cathode. Families of compounds that have yet to be investigated are scarce, however one such family are those containing fluorides. By introducing a more electronegative anion, higher oxidation states of transition metals can be stabilized which opens up the opportunity of higher redox potentials as well as the possibility of more than one Li+ ion deintercalation per transition metal; a phenomenon yet to be observed in Li-ion batteries. Lithium-transition metal-fluorides have potential as candidates for high voltage, low molar mass cathode materials, resulting in high energy density.

Thus far, it has only been shown that lithium intercalation into Li3MF6 (MIII to MII) structures has been possible2,3, while the elusive reversible deintercalation (MIII to MIV) has not been achieved. Our preliminary studies show that in certain conditions, reversible deintercalation of these family of compounds is possible providing the synthetic methods are carefully controlled. Previously reported synthetic routes for these class of materials utilized aqueous precipitation methods and sol-gel processing methods involving water. It is already a well-established principle that at high voltages, run-away reactions between the electrolyte and water can occur. By synthesizing these materials in a completely air and water free environment, we have observed evidence of reversible oxidation and changes in crystals structure of Li3VF6 through electrochemical analysis at 4.4V vs Li. Changes in the oxidation state of the central transition metal were confirmed by hard x-ray absorption spectroscopy and changes in the crystal structure were shown using high resolution x-ray diffraction. We are currently investigating this family of materials with other transition metals and anticipate these compounds will show similar results.

These promising results have given hope to redox chemistry at much higher operating voltages than has been previously observed for fluoride compounds.

1. K. Mizushima, P. C. Jones, P. J. Wiseman, and J. B. Goodenough, Mater. Res. Bull., 15, 783–789 (1980).

2. A. Basa, E. Gonzalo, A. Kuhn, and F. García-Alvarado, J. Power Sources, 207, 160–165 (2012).

3. G. Lieser et al., J. Power Sources, 294, 444–451 (2015).
Iron Oxalates As Novel Electrode Materials for Li-Ion and Na-Ion Batteries
Authors: Yao Wenjiao , Armstrong Anthony Robert , Lightfoot Philip
Published: February 2020

There is intensive research activity targeted on developing new electrode materials for the next generation of rechargeable lithium batteries, particularly for large-scale use in future hybrid electric or pure electric vehicles and in stationary energy storage of solar/wind power [1-3]. Polyoxyanion compounds are receiving considerable interest as cathodes since the strong binding of the oxygen enhances stability and thus safety, compared with transition metal oxides. The electronic inductive effect shifts the d-states of the transition metal ions and hence the redox potentials, providing a means of tuning the latter. Phosphate materials, particularly LiFePO4, have been extensively studied and continue to be important [2,3]. Recent work on oxalates by Tarascon and co-workers [4,5] has demonstrated the possible use of oxalate materials as a new class of polyoxyanion.  Here we report the synthesis and characterization of hitherto-unknown alkali metal iron compounds in the oxalate system with new compositions and structures. The three dimensional framework structures were determined by single crystal X-ray diffraction, with an example shown in Fig. (a).  All the materials displayed redox activity vs. either Li or Na, depending on the compound with stable cycling as shown in Fig. (b).

(1) B. L. Ellis, K. T. Lee and L. F. Nazar, Chem. Mater., 2010, 22, 691;

(2) J. B. Goodenough and Y. Kim, Chem. Mater., 2010, 22, 587.

(3) A. K. Padhi, K. S. Nanjundaswamy, and J. B. Goodenough, J. Electrochem. Soc. 1997, 144, 1188.

(4) H. Ahouari, G. Rousse, Y. Klein, J.N. Chotard, M.T. Sougrati, N. Recham, J.M. Tarascon. Solid State Sci. 2015, 42(6), 13.

(5) H. Ahouari, G. Rousse, J.R. Carvajal, M.T. Sougrati, M. Saubanere, M. Courty, N. Recham, J.M. Tarascon. Chem. Mater., 2015, 27, 1631.

Figure 1
Detection of Graphite Intercalation Compound Stages Using in-Operando 7Li NMR
Authors: Lorie Lopez Jose L. , Grandinetti Philip J. , Co Anne C.
Published: February 2020

Operando spectra of a battery often consists of strongly overlapping resonances due to the compositional complexity and a mix of broad resonances. In the case of NMR spectroscopy, one could appeal to magic angle spinning (MAS) to remove some of these line broadenings and improve resolution. Unfortunately, eddy currents arising in metallic current collectors as well as in metallic electrode materials pose numerous experimental challenges.

Reported herein is an NMR method we developed that (1) improves the resolution of overlapping resonance which allows the identification of closely related features, but more importantly, the method (2) enhances the signals due to the formation and removal of species during the cycling of a battery. These spectra not only provide better resolution but also offer a more direct comparison of the species that are formed to the electrochemical current measured at each potential/time and reveal which spectra components are correlated to the chemical transformation at a specific potential.