bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward Maximized Volumetric Energy Density Using Graphite Via Polymer Coating with High Degree of Electrolyte Impregnation
Authors: Sung Jaekyung , Cho Jaephil
Published: February 2020

Development of electric vehicles and portable electronics triggers a research boom for the advanced lithium ion batteries (LIBs) with high energy density. For these reasons, High specific capacity anodes including Sn, Si and Ge with the specific capacity over 1500 mAh g−1 has been highlighted as alternative anodes to achieve the high energy LIBs. Although the huge volume change considered as the main reason of short cycle life upon repeated charging-dischrage process has been recently handled through the nano-engineering, its utilization as a commercial anodes has been still hindered when considering the low volumetric energy density affected by the several factors (low coulombic efficiency, high electrode swelling ratio, high working voltage and low cycling performance). On the other hand, conventional graphite exhibits the low working voltage and high cycling stability, and its high true density of 2.25 g cc−1 and low expansion ratio of 8% during cycling could lead to the high theoretical volumetric energy density of over 770 Wh L−1. However, density of the currently used electrode using conventional graphite anodes is 1.4 ~ 1.6 g cc−1 bringing about volumetric energy density of 550 Wh L−1. In case of the high electrode density of over 1.9 g cc−1, the poor electrolyte impregnation causes the unreacted active material with electrolyte upon cycling, which leads to the unbalance of N/P ratio (much higher areal capacity of cathode than those of anode) resulting in the Li metal plating. Therefore, Promoting the electrolyte penetration to electrode which is comprised of the highly densified active materials is key factors to meet the high energy density lithium ion batteries by using conventional graphite anodes. In this study, we synthesized cyanoethyl polyvinyl alcohol (PVA-CN) having feature of high degree of impregnation and coated on conventional graphite surface. Because of the PVA-CN with the higher permittivity which is one of critical factors determining the impregnation of electrolyte than these of other polymer such as SBR and PVDF, PVA-CN coated graphite composite demonstrated high cycling performance under the high electrode density of 1.9 g cc−1 without any Li plating, leading to the high volumetric energy density of over 650 Wh L−1.
Large Batch Coating Process for Improving Thermal Stability of NCM622 Cathode
Authors: Durham Jessica L , Fister Timothy T , Murphy Michael J. , Wang Lixin , Zhou Fu , Lu Lei , Kim Kitae , Johnson Derek C , Lipson Albert L.
Published: February 2020

Nickel-rich cathodes such as LiNi0.6Co0.2Mn0.2O2 (NCM622) have received considerable attention as a result of their high delivered capacity. However, owing to high nickel content, NCM622 cathodes suffer from reduced cycle life and thermal stability compared to lower nickel content NCM523 and NCM333 cathodes. (1) Traditional approaches to coating and doping, including exploration of various coating (Al2O3, AlF3, SiO2) and dopant (Al3+, Mg2+, F-) species which either act as a passivating layer between the cathode surface and reactive electrolyte or to stabilize the structure of the material, have been employed in the past to improve the performance of Ni-rich cathodes. (2-9)

This presentation demonstrates the effectiveness of a large batch (i.e. 500 grams) coating process to deposit either AlF3 or ZnO on NCM622 cathode material. The process is a dry mixing technique wherein the coating is applied using powerful mechanical energy to induce mechano-chemical reactions between the surface of NCM622 and AlF3 or ZnO. SEM imaging and EDX mapping illustrate that the size or morphology of the secondary particles is not affected by the process and the coating species is well-distributed among the bulk. Differential scanning calorimetry (DSC) and temperature-depending X-ray diffraction (XRD) were conducted to monitor the thermal stability of AlF3 and ZnO coated NCM622. Temperature-dependent XRD shows the structural degradation of the layered NCM622 structure to a non-layered rock-salt structure as a function of temperature. The peak positions in the DSC correspond directly to the c lattice parameter decreasing, which is caused by oxygen release, and the conversion to a rock-salt phase. These results indicate how AlF3 and ZnO coatings alter the collapse and phase transition of the delithiated NCM622 during heating.

References

(1) Liu, W.; Oh, P.; Liu, X.; Lee, M.-J.; Cho, W.; Chae, S.; Kim, Y.; Cho, J. Chem. Int. Ed.
2015, 54, 4440-4457.

(2) Mohanty, D.; Dahlberg, K.; King, D. M.; David, L. A.; Sefat, A. S.; Wood, D. L.; Daniel, C.; Dhar, S.; Mahajan, V.; Lee, M.; Albano, F. Reports
2016, 6, 26532.

(3) Han, B.; Paulauskas, T.; Key, B.; Peebles, C.; Park, J. S.; Klie, R. F.; Vaughey, J. T.; Dogan, F. ACS Appl. Mater. Interfaces
2017, 9, 14769-14778.

(4) Liao, J.-Y.; Manthiram, A. Power Sources
2015, 282, 429-436.

(5) Du, K.; Xie, H.; Hu, G.; Peng, Z.; Cao, Y.; Yu, F. ACS Appl. Mater. Interfaces
2016, 8, 17713-17720.

(6) Zhou, P.; Zhang, Z.; Meng, H.; Lu, Y.; Cao, J.; Cheng, F.; Tao, Z.; Chen, J. Nanoscale
2016, 8, 19263-19269.

(7) Woo, S.-U.; Yoon, C. S.; Amine, K.; Belharouak, I.; Sun, Y.-K. Electrochem. Soc.
2007, 154, A1005-A1009.

(8) Hu, G.; Zhang, M.; Liang, L.; Peng, Z.; Du, K.; Cao, Y. Electrochimica Acta
2016, 190, 264-275.

(9) Krishna Kumar, S.; Ghosh, S.; Ghosal, P.; Martha, S. K. Power Sources
2017, 356, 115-123.
Melt-Process for the Preparation of Porous Composite Electrodes for Battery Application
Authors: Verdier Nina , El Khakani Soumia , Lepage David , Prébé Arnaud , Dollé Mickael , Rochefort Dominic
Published: February 2020

Lithium-ion batteries have become the dominant technology for electrochemical energy storage. They have been used in electronic portable devices for decades and now taking the lead in the transportation sector in electrical vehicles. As it has long been known, the release of CO2 from combustion engine-powered constituted a significant proportion of our global emission of greenhouse gases. In order to reduce this proportion, efforts are being deployed to increase the market penetration of electric vehicles which puts a growing pressure on the production of lithium-ion batteries. As a result, this production is predicted to rapidly and sharply grow in the next few years.

This fast development raises novel issues regarding the electrode production process and its impact on the environment. Currently, most of the electrode fabrication processes require organic solvent such as N-methyl-2-pyrrolidone (NMP), which is toxic and costly. It is therefore essential to find an alternative which is more sustainable that the solvent process yet that meets requirements of scalability, cost and productivity. In this context, we propose a new approach to electrodes fabrication process developed by our industrial partner Hutchinson (Patent US20130244098A1). It consists of a melt process which is well-known in the polymer industry to make composites. As such, our process does not require any solvent. In our study, we optimised the electrode formulation for power applications.

In this presentation, we will report the different steps of the new melt process. The active materials and the conductive carbons used are the same as in the conventional wet process, but the binder needs to be chosen with care. Indeed, due to constraints in terms of temperature, shear forces and of the mixing process itself, the binder must be a heat-tolerant elastomer, to allow good mixing properties to the blend and flexibility to the resulting electrode. As an alternative to the most commonly-used binder, PVdF, a lower-cost commercial elastomer, Hydrogenated Nitrile Butadiene Rubber (HNBR), was used as the binder. To evaluate its compatibility and performance in lithium-ion battery composite electrodes, it was first compared to PVdF with the common wet process to make electrodes. After the validation of HNBR as a binder, it was used with the melt-process. Power testing and cycling performances of electrodes made with different active materials will be presented, showing the feasibility of electrodes and the versatility of the melt-process.
The Structural Stabilization Effect of Tungsten Doping on Layered LiNiO2 Cathodes for High-Energy-Density Lithium-Ion Batteries
Authors: Ryu Hoon-Hee , Nam Gyeong Won , Sun Yang-Kook
Published: February 2020

Ni-rich layered transition-metal (TM) oxides, e.g., Li[Ni
x
Co
y
Mn1-x-y]O2 (NCM) and Li[Ni
x
Co
y
Al1-x-y]O2 (NCA), have attracted considerable attention as cathode materials for Li-ion batteries (LIBs) and have been deployed in commercial EVs.1 In order to increase the energy density and satisfy the target driving range, the Ni content in NCM and NCA cathodes has been progressively increased, from 33% to 85%.2,3 At the end of this strategy lies LiNiO2 (LNO), in which all of the Co and Mn is replaced by Ni, yielding a high specific capacity of 250 mAh g-1 at a relatively low material cost.3 However, it was notoriously difficult to use in practice because LNO undergoes several phase transition during Li+ intercalation and deintercalation, which can lead to severe capacity fading.4 In addition to the detrimental phase transition occurring in the deeply charged state and the parasitic reactions of reactive Ni4+ at the surface cause the capacity fading of cathode materials.

In the present study, we investigated the effect of W doping on the structural stabilization during the electrochemical process. To systematically investigate the effect of W doping, a series of W-doped LNO cathodes with 1.0, 1.5, and 2.0 mol% W were synthesized using an optimized co-precipitation process. The structural behavior observed via in situ X-ray diffraction (XRD) was correlated to the electrochemical performance of the W-doped cathodes.

References

S.-T. Myung, F. Maglia, K.-J. Park, C. S. Yoon, P. Lamp, S.-J. Kim, Y.-K. Sun, ACS Energy Lett.
2017, 2, 196.

H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources
2013, 233, 121.

H.-H. Sun, W. Choi, J. K. Lee, I.-H. Oh, H.-G. Jung, J. Power Sources
2015, 275, 877.

C. S. Yoon, D.-W. Jun, S.-T. Myung, Y.-K. Sun, ACS Energy Lett.
2017, 2, 1150.
(Invited) Low-Cobalt and Cobalt-Free Cathodes for Next-Generation Lithium-Ion Batteries
Authors: Manthiram Arumugam
Published: February 2020

Lithium-ion batteries have become an integral part of our daily life with an exponential growth in portable electronics during the past couple of decades. They are now being intensively developed for the electrification of the transportation sector. They also have the potential to penetrate into the utility industry for the grid storage of electricity produced from renewable sources like solar and wind. As we move from small batteries used in portable devices to large batteries used in electric vehicles and grid storage, cost becomes a major factor in addition to other factors like cycle life, safety, energy density, charge-discharge rate, and environmental impact. Lithium-ion batteries for portable devices and electric vehicles currently employ layered LiNi1-x-yMnxCoyO2 cathodes with a significant amount of cobalt. Unfortunately, cobalt has limited abundance and is expensive, which could pose serious problems for a widespread deployment of lithium-ion batteries for electric vehicles and grid storage. Therefore, it is critical to develop cathodes with low-cobalt content or no-cobalt. Accordingly, the presentation will focus on the design and development of low-cobalt and cobalt-free layered oxide cathodes for next-generation lithium-ion batteries.

Layered LiNi1-x-yMnxCoyO2 cathodes with cobalt content as low as 6% for M in LiMO2 or no cobalt are synthesized with a desired optimum particle size by a coprecipitation of the hydroxide precursors employing a tank reactor. The hydroxide precursors are then fired at desired temperatures with lithium hydroxide with or without appropriate dopants to obtain the layered LiMO2 oxides. After an in-depth characterization, the oxide cathodes are evaluated by pairing with graphite anodes in full lithium-ion cells. Both the oxide cathodes and graphite anodes are characterized with a suite of analytical techniques before and after cycling the full cells for thousands of cycles to develop a fundamental understanding of the factors that lead to performance degradation. The analytical techniques include in-situ X-ray diffraction, X-ray photoelectron spectroscopy, time of flight secondary ion mass spectrometry, scanning electron microscopy, and high-resolution transmission electron microscopy. Extensive data on cathode compositions, such as LiNi0.94Co0.06O2 and LiNiO2 with and without doping will be presented. Furthermore, the thermal stability and air-stability of the samples and the effects of doping on them will be discussed. Stabilized cathode compositions with capacities as high as 220 mA h g-1 and long cycle life will be presented.
Compositionally and Structurally Re-Designed High-Energy Li[Ni0.886Co0.049Mn0.050Al0.015]O2 Cathode for Lithium Batteries
Authors: Kim Un-Hyuck , Nam Gyeong Won , Sun Yang-Kook
Published: February 2020

A hybrid cathode, Li[Ni0.886Co0.049Mn0.050Al0.015]O2, consisting of a core of Li[Ni0.934Co0.043Al0.015]O2 encapsulated by Li[Ni0.844Co0.061Mn0.080Al0.015]O2 is prepared. This core/shell-type structure combining a Ni-enriched Li[Ni
x
Co
y
Al1-x-y
]O2 (NCA) cathode with an Al-doped Li[Ni
x
Co
y
Mn1-x-y
]O2 (NCM) cathode provides an exceptionally high discharge capacity of 225 mAh g-1 at 4.3 V and 236 mAh g-1 at 4.5 V. The hybrid cathode also exhibits microstructural attributes that are beneficial to long-term cycling stability, namely, spatially correlated peripheral primary particles that are crystallographically textured to expedite Li intercalation and nano-sized core primary particles retard the propagation of interparticle microcracks. In addition, ordered intermixing of Li and transition metal ions is observed in the cycled hybrid cathode. This cation ordering stabilizes the host structure during cycling and facilitates Li intercalation. These structural features allow the hybrid cathode to retain 91% of its initial capacity after 1000 cycles, which easily surpasses the performance of currently available cathodes.

H.-J. Noh et al., J. Power Sources 233 (2013) 121–130.

Y.-K. Sun et al., Nat. Mater. 8 (2009) 320–324.

W. Jun et al., Chem. Mater. 29 (2017) 5048–5052.

H. Kim et al., Adv. Energy Mater. 6 (2016) 1601417.
Spherical Shaped Particle of Randomly Packed LiFePO4 Nanoplates for High-Rate of Li-Ion Batteries
Authors: Oh Woong , Patil Virendra , Yoo Jong Won , Yoon Won-Sub , Yi Gi-Ra
Published: February 2020

Energy storage is the key factor for saving and using renewable energy. Among the various energy storage devices, Li-ion battery is the most promising storage device owing to its high energy density, efficiency and cycle life. Not only for the small application like mobile phone and laptop computer but also electric vehicles (EVs) and massive energy storage system (ESS), numerous applications have been used Li-ion battery. However its high energy density is like a double-edged sword, the safety issues have been a problem for the practical market. The safety problems from the Li-ion battery usually come from thermal runaway, which is mainly come from oxygen release from the cathode material. Lithium iron phosphate (LFP) has PO4 polyanion that oxygen atom is strongly bonded with phosphorus and prevents oxygen release, therefore, it is well known as the safe cathode material for the Li-ion battery. Also for the high power battery applications, LFP is a promising material owing to the ability of high-rate charge and discharge performance. For the high rate availability on LFP material, two important key factors should be satisfied; one is fast ion diffusion inside the material and the other is high electric conductivity. The Li-ion diffusivity coefficient and electron conductivity are intrinsic properties of the material, however, particle size or morphology and conducting agent coating can raise the speed of diffusion and conduction.

Here, we demonstrated those factors by solvo-thermally synthesized plate shape nanoparticle and spherical secondary particle with carbon coating using spray-drying. The nanoparticle has a flat shape in b-axis, therefore, diffusion speed increase because the diffusion distance of lithium is greatly reduced. The nanoparticle without spray-drying showed low capacity and also poor C-rate performance even with the carbon coating. Besides, after forming the spherical particles, it showed 162mAh/g of initial capacity at the 0.1C rate and maintains more than 80% of initial capacity (~130.91mAh/g) at the 50C rate. Moreover, electrode density which is the intrinsic weakness of nanoscale electrode material has been improved and the spheres carried out excellent cycling ability which shows 98% capacity retention over 500cycles at 1C after the high C-rate test. In order to analyze the causes of such good characteristics, morphology and crystallographic directions were confirmed by SEM and TEM image, and electrical conductivity and diffusion coefficient were calculated by using Cyclic Voltammetry (CV), Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS).

More details will be discussed at the meeting.
Understanding Local Distortions in NMC Cathodes
Authors: Yin Liang , Li Zhuo , Mattei Gerard , Khalifah Peter
Published: February 2020

Li(NixMnyCoz)O2 (NMCs) layered oxides are very promising cathodes for Li-ion batteries due to their high theoretical capacities and high working voltages. However, a variety of local distortions exist in NMC compounds and likely influence their electrochemical performance. Identifying and further quantifying these local distortions is important for understanding their structure/property relationships and thus providing insights into how to produce NMC samples with optimal properties. In this work, a comparative study of the local structure of many NMC compositions was carried out using synchrotron and neutron total scattering data. Novel methods were developed to quantify the degree of local ordering to investigate its dependence on sample composition.
(Invited) Preserving a High Energy Density of the Lithium-Rich Layered Oxides (LLO) and New Lithium Diffusion Model for Llo
Authors: Kang Kisuk
Published: February 2020

Lithium-rich layered oxides (LLOs) are considered promising cathode materials for lithium-ion batteries because of their high reversible capacity, which is attributed to the exploitation of the novel anionic redox in addition to the conventional cationic redox process. Cobalt-free layered lithium-rich nickel manganese oxides, Li[LixNiyMn1
−
x
−
y]O2, are one of the promising positive electrode materials for lithium rechargeable batteries because of their high energy density and low materials cost. However, substantial voltage decay is inevitable upon electrochemical cycling, which makes this class of materials less practical. It has been proposed that undesirable voltage decay is linked to irreversible structural rearrangement involving irreversible oxygen loss and cation migration. In the first part of my talk, we demonstrate that the voltage decay of the electrode is correlated to Mn4+/Mn3+ redox activation and subsequent cation disordering, which can be remarkably suppressed via simple compositional tuning to induce the formation of Ni3+ in the pristine material. By implementing our new strategy, the Mn4+/Mn3+ reduction is subdued by an alternative redox reaction involving the use of pristine Ni3+ as a redox buffer, which has been designed to be widened from Ni3+/Ni4+ to Ni2+/Ni4+, without compensation for the capacity in principle. Negligible change in the voltage profile of modified LLO is observed upon extended cycling, and manganese migration into the lithium layer is significantly suppressed.

In the second part of the talk, I will discuss about transition metal (TM) migration, which is now understood to be the critical factor triggering the anionic redox as well as the phase transition, although the origin is still under debate. A better understanding of the specific TM migration behavior and its effect during charge/discharge would thus enable further development of this class of materials. I will show that the unique TM migration during charge/discharge significantly alters the lithium diffusion mechanism/kinetics of LLO cathodes. I present clear evidence of the much more sluggish lithium diffusion occurring during discharge (lithiation) than during charge (de-lithiation), which contrasts with the traditional lithium diffusion model based on simple topotactic lithium intercalation/deintercalation in the layered framework. The reversible but asymmetric TM migration in the structure, which originates from the non-equivalent local environments around the TM during the charge and discharge processes, is shown to affect the lithium mobility. This correlation between TM migration and lithium mobility led us to propose a new lithium diffusion model for layered structures and suggests the importance of considering TM migration in designing new LLO cathode materials.
Anomalous Segregation in Lithium-Rich Layered Oxide Uncovers New Theoretical Design Rule for Stable Cathode in Lithium-Ion Battery
Authors: Xin Huolin , Lin Ruoqian , Hu Enyuan , Bak Seong-Min , Yu Xiqian , Persson Kristin A , Wu Qin , Yang Xiao-Qing
Published: February 2020

Here we report the TEM, X-ray, and first-principle investigation of a promising high-capacity lithium-rich 3d-4d (Mn-Ru) transition-metal layered compound. The incorporation of 4d transition metals here offers an uncharted phase space for mechanistic exploration as compared to the well documented 3d transition metal (TM) oxides. Using state-of-the-art electron and X-ray based techniques, we find surprisingly, after cycling, ruthenium segregates out as metallic nanoclusters on the reconstructed surface. Our calculations show that the unexpected ruthenium metal segregation is due to its thermodynamic insolubility in the oxygen deprived surface. This insolubility can disrupt the reconstructed surface, which explains the formation of a porous structure in this material. The revealed mechanism allows us to provide predictive guidance for the future design of lithium-rich as well as stoichiometric layered cathode materials.

This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, and the Scientific Data and Computing Center, a component of the Computational Science Initiative, at Brookhaven National Laboratory under Contract No. DE-SC0012704. Dr. Enyuan Hu, Dr. Seongmin Bak, and Dr. Xiao-Qing Yang were supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program, including Battery500 Consortium under Contract DE-SC0012704. Work done by R.Z. is partially supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Award Number: DE-EE0008444. The work at IOP was supported by funding from Ministry of Science and Technology of China (Grants 2016YFA0202500) and the National Natural Science Foundation of China (51822211). H.C. and J-C.Z. were supported by the National Natural Science Foundation of China (51661135011). This research used resources 8-ID, 23-ID-2, and 28-ID-2 of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. This research used resources of beamline 8.0.1 of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. We acknowledge the technical support from beamline scientists Dr. Jianming Bai and Dr. Eric Dooryhee at the XPD beamline of NSLSII.
Drying Process Research on High Energy Density LiNi1/3Co1/3Mn1/3O2 Electrode in Li-Ion Batteries
Authors: Fu Yanbao , Song Xiangyun , Liu Gao , Battaglia Vince
Published: February 2020

The most essential parameters in batteries are energy density, cost and safety. The cell energy density depends on the cell chemistry and geometry. In previous research, we made ultra-thick electrodes with optimum energy and power density for electric vehicles (EVs) and hybrid EVs (HEVs). Currently we developed a methodology such that the temperature of the laminates reached the temperature of the drying oven within a minute and drying of thick laminates at rates approaching industry (< 10 min). We examined the role of drying conditions of coated slurries on electrode morphology, binder distribution, binder crystallinity and in turn on the electrode’s mechanical and electrochemical properties. In our research, drying temperature has an impact on the components distribution in the electrode. The crystallinity of binder (poly vinylidene fluoride, PVDF) in the electrode is also dependent on drying temperature. From room temperature to 180 °C, the crystalline phase of PVDF membrane switched from β-phase to α-phase. The ionic conductivity is different in the two phases, which leads to different electrochemical performance of electrodes.

Figure 1
Cathode Additive for LiNi0.8Co0.1Mn0.1O2 /Li Metal Battery Operating at 4.3V
Authors: Yoo Minjeong , Park Eun Ji , Ahn Jinhyeok , Im Jinsol , Jang Eun Kwang , Cho Kuk Young
Published: February 2020

Lithium-ion batteries (LIBs) are widely used in portable electronics. However, safe, long-term stable LIBs with higher energy density need to be developed to meet the increasing demand for large-sized devices such as electric vehicles and energy storage systems. For high energy density, further development of cathode materials is still considered as capacity and/or operating voltage are pursued. Among the various cathode materials, Ni-rich LiNixCoyMn1-x.yO2 materials with x ≥ 5, especially LiNi0.8Co0.1Mn0.1O2 (NCM811) have attracted much attention recently owing to their high theoretical specific capacity of 200 mAh/g. However, LiNi8Co0.1Mn0.1O2 operated beyond 4.3V suffers serious capacity fading caused by continuous electrolyte decomposition, despite an increase in the capacity in the early cycles. To overcome this obstacle, the addition of small amounts of other components into the electrolyte system without changing the bulk properties is a very promising approach. In this study, we introduced a cathode additive and investigated the effect of functional electrolyte for the application NCM811 based Lithium metal batteries. Our results indicate the significance of novel additive for promising high voltage operation of next-generation cathode materials.
Electrochemical Modeling on Crack Propagation within Ni-Rich Layered Cathode Materials
Authors: Park Sunho , Park Joonam , Song Jihun , Ryou Myung-Hyun , Lee YongMin
Published: February 2020

Rechargeable lithium-ion batteries (LIBs) are being actively applied to energy storage systems (ESSs) and electric vehicles (EVs) because of their high energy density and long-life characteristics. Essential to the success of these efforts is warranty for not only battery performance but also reliability, which needs to understand the underlying degradation mechanism. Particularly, as the Ni content in cathode active materials increases, crack formation and propagation within the particle has been investigated as one of main causes for LIB degradation. However, although the formation of this crack is highly related to the number of cycles and the state of charge (SOC), the related research is still stayed in place.

In this study, a new electrochemical model for lithium ion batteries is proposed based on theoretical equations of crack propagation. We aim to model the phenomenon of crack propagation after cycling in different depth of discharge (DOD) levels using 18650 cells, whose chemistry is LiNi0.8Co0.15Al0.05O2/Graphite. In particular, since LiNi0.8Co0.15Al0.05O2 has a form of secondary particle, its degradation is closely related to cracks within the particle when it is charged to high voltage over long-term cycling. And it has been found the range of SOC has a greater impact on degradation than the number of cycles. We try to establish the model by giving the degradation impact of SOC and the number of cycles differently. This choice of model brings a cycle life prediction with a few parameters to be fitted to particular cells.
Implementation of Tin Dioxide/Graphene/Graphene Oxide for High Capacity and Long Cycle Life Lithium Ion Batteries
Authors: Dorvilien Valerio , LopezdeVictoria Monica , Dorvilien Valerio , Mendoza Frank , Weiner Brad R. , Morell Gerardo
Published: February 2020

We explored a non-conventional process to synthesize SnO2/G/GO composite powder which is a conformal structure that was characterized under different techniques. Comprehensive analysis of the structural and chemical properties reveals that the material consists of highly dispersed SnO2 nanoparticles in G/GO matrix.

We examine the electrical conductivity of the electrodes by atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The SnO2/G/GO composite exhibited high discharge capacity and excellent electrochemical performance as anode material for lithium ion Battries. The quantitative/qualitative results show that G/GO is providing contact areas which results in more energy density at the interface electrode/electrolyte and that the SnO2 provides additional ions to the EDL and the electrochemical process.
Obtaining Reliable Kinetics from Nanosized Battery Materials
Authors: Schougaard Steen Brian
Published: February 2020

One of the many frontiers of energy storage is high power, both on charge and on discharge. Consequently, development of materials that can support high current densities are in vogue. This challenge is here that the mass transport in structures that support ion insertion/dis-insertion is known to be slow. Approaches to address this challenge includes increasing the operational temperature and nanosizing the electroactive active materials. Nanosizing, however leads to severe problems related to obtaining good electronic contact as well as questions regarding the uniformity of the performing across a large population of particles. In this talk we will discuss our recent development of techniques to overcome this these challenges, including techniques that rely on electrochemistry as well as purely chemical ones. Special focus will be given our hyphenated technique providing structural information while providing full charge (disinsertion) in seconds.
Step Potential Electrochemical Spectroscopy (SPECS) Analysis Using Various Diffusion Model for Comparison of Spinel LiMn2O4 As Cathode Material for Li-Ion Battery (LIBs)
Authors: Ahmed Zahoor , Donne Scott W
Published: February 2020

Step potential electrochemical spectroscopy (SPECS) or current transient technique for determining the mechanisms by which lithium ion transport through spinel LiMn2O4 positive electrode material during intercalation/de-intercalation was investigated. In this work, step potential electrochemical spectroscopy (SPECS) in three electrode systems have been conducted on spinel prepared by solid state and sol-gel methods. Based on the data obtained from the SPECS experiment the data has been fitted with planar, double planar and a spherical diffusional model, to better understand the diffusional mechanism and to obtain an accurate diffusional parameter for these materials. Theoretical models clearly illustrate that both spherical and double plane diffusion models are in excellent agreement with experimental data from beginning short time of the potential step till the end for long time 3600s. This work aims to develop a more comprehensive analysis technique for future work. By using SPECS technique, the various curves for Cottrellian type behaviour were also investigated, such as I(t)*sqrt(t) vs decimal logarithm as Li-ion insertion/de-insertion into the spinel. The crystal structure, materials morphology and elemental composition were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy (EDS), and high-resolution transmission electron microscopy (HR-TEM). These experiments reveal the potential benefits of understanding Li-ion diffusion of spinel LiMn2O4 for high-power lithium-ion batteries (LIBs) storage performance.
(Invited) Requirements and Challenges for Next Generation Automotive Batteries
Authors: Gittleson Forrest S
Published: February 2020

E-mobility is at a tipping point with increasingly optimistic forecasts for the future market share of electric vehicles. However, for electrified vehicles to achieve mass-market penetration, new powertrains must achieve a reasonable balance between driving range, power, charge rate, safety and cost. Optimization of the battery pack down to the cell, electrode and material levels offers the potential for many performance improvements, yet each change necessitates significant re-tailoring of a cell. Such multivariable optimization requires high-throughput evaluation methods as well as a deep understanding of electrochemical, chemical and mechanical fundamentals. To apply demanding automotive requirements to new battery technologies, BMW Group works with academic, national lab, and industry partners to understand the impacts of each cell design decision. Some innovations (e.g. advanced electrolytes) are challenging to discover but simple to implement, while others (e.g. high-Si content anodes, all-solid-state electrolytes) require significant R&D inputs in both discovery and scalability. This presentation will outline the opportunities and limitations of various cell and material concepts from a car manufacturer’s point of view. Key challenges will be addressed with examples from BMW research projects.
A Scalable Froth-Flotation Separation Process for Direct Recycling of Li-Ion Batteries and Its Technical Feasibility
Authors: Shin Hosop , Zhan Ruiting , Dhindsa Kulwinder , Pan Lei , Han Taehee
Published: February 2020

The increasing demand for Li-ion batteries (LIBs) in hybrid and electric vehicles had led to a significant increase in the volume of new and end-of-life LIBs. For this reason, recycling of spent LIBs has attracted significant attention in recent years for future sustainability. Different from existing recycling methods such as pyrometallurgical and hydrometallurgical methods, direct recycling method recovers cathode and anode active materials directly in reusable forms at a low cost. This process consists of two steps: 1) liberation and separation, and 2) re-functionalization (or re-lithiation). Many previous studies have been focusing on the second step only. To successfully implement the direct recycling process, development of a scalable and environmentally friendly separation process for battery active materials while preserving their functional integrity is necessary. To date, no studies have been conducted to evaluate the technical feasibility of such a scalable separation process for the direct recycling method.

In this work, a water-based recycling process was developed to recover cathode active materials from LIBs. In this recycling process, froth flotation technique was used to separate cathode active materials from a mixture of cathode and anode materials. A variety of electrochemical analyses of the recycled cathode active materials were systematically conducted to evaluate technical feasibility and understand current challenges of this recycling process. The present research demonstrated that the use of kerosene as the collector in the froth flotation process improved the purity of produced cathode active materials, and the recycled cathode materials preserved their original electrochemical reactivity. Cycle performance (up to 200 cycles) and rate capability (up to 1C) of the recycled cathodes were comparable to those of a pristine cathode. However, the reversible capacity of the recycled cathodes was slightly lower than that of a pristine cathode because of cell polarization. The polarization caused by electrode wettability and surface impurities on the recycled cathodes was identified as a key challenge that needs to be addressed further. This work will provide valuable insights into further development of a froth flotation-based recycling process which can be implemented in the direct recycling process.
Recovery of Unwanted Lithium from Graphite Anodes Via Thermal Gradient
Authors: Atkinson Robert W. , Carter Rachel E. , Love Corey T
Published: February 2020

Thermal management is a known design consideration for safe and stable cycling of Li-ion batteries. Active thermal management systems attempt to maintain isothermal control to limit thermal excursions that can lead to premature cell performance loss and safety failures. Low temperature cycling is one example of unsafe Li-ion battery operation, which has been shown to limit cycle life by lithium plating and can also lead to dendrite nucleation and growth that can cause internal short circuits and battery failure. However, it can be assumed that these engineering controls cannot consistently maintain the safe isothermal condition and localized thermal gradients will develop within cells.

We previously showed that the application of an external thermal gradient has a profound effect on cell electrochemical processes. For lithium metal symmetric cells, the direction of an interelectrode thermal gradient dictates lithium plating morphology and determines whether unstable, dendrite growth or stable plating occurs (1). We have also demonstrated that applying a thermal gradient (cold anode, warm cathode) allows plating lithium on graphite on-demand, dramatically reducing cell capacity by loss of lithium inventory (2). In this way, a thermal gradient rapidly incites realistic cell failure modes, accelerating testing to battery failure to enable improved understanding of battery failure.

This talk focuses on the utility of reversing the direction of interelectrode thermal gradients to strip lithium from the graphite electrode. We use post mortem materials characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy to characterize texture and morphology of the plated and lithium metal on graphite and confirm its recovery. A thermal gradient effectively restores battery health by modulating plating to recover lithium inventory and battery capacity; this thermal gradient reversal prevents internal short circuits from dendrite growth and ultimately extends battery lifetime in NMC|graphite cells. In addition to post mortem materials characterization, we use electrochemical impedance spectroscopy (EIS) and incremental capacity analysis to monitor lithium plating and stripping modulation.

References

A. Mistry, C. Fear, R. Carter, C. T. Love and P. P. Mukherjee, ACS Energy Letters, 4, 156 (2018).

R. Carter and C. T. Love, ACS Appl Mater Interfaces (2018).
Desalination Technologies Utilizing Solar Energy
Authors: Zheng Yanjie , Hatzell Kelsey B.
Published: February 2020

Geographic areas that are rich in seawater or brackish water but lack freshwater resources require desalination technologies in order to meet water needs. Desalination processes are energy intensive, and thus there is a growing interest in coupling desalination with solar energy technologies (i.e. electrical or thermal energy sources). Three main approaches are: (1) photovoltaic-reverse osmosis (PV-RO), (2) solar-thermal desalination, and (3) solar-electrochemical1-4. The first approach creates electrical energy to drive a pressure driven membrane desalination approach and the second approach creates heat to drive a phase change separation process. Finally, the third approach is potentially the least well studied because most electrochemical separation technologies still reside at the benchtop scale. In this poster we theoretically evaluate the energetics and technoeconomics of various solar-desalination schemes and assess the potential of electrochemical technologies for industrial separations applications.

[1] Pugsley, A., Zacharopoulos, A., Mondol, J. D., & Smyth, M. (2016). Global applicability of solar desalination. Renewable energy, 88, 200-219.

[2] Mistry, K. H., McGovern, R. K., Thiel, G. P., Summers, E. K., Zubair, S. M., & Lienhard, J. H. (2011). Entropy generation analysis of desalination technologies. Entropy, 13(10), 1829-1864.

[3] Zheng, Y., Zhao, Y., Liang, S., & Zheng, H. (2018). Thermo-Economic Optimization of an Idealized Solar Tower Power Plant Combined with MED System. Entropy, 20(11), 822.

[4] Warsinger, D., Mistry, K., Nayar, K., Chung, H., & Lienhard, V. (2015). Entropy generation of desalination powered by variable temperature waste heat. Entropy, 17(11), 7530-75
Investigating Cathode Dissolution By Homogeneous Sol-Gel Coating on Manganese Dioxide Nanofibers to Extend Battery Performance
Authors: Haddad Milan Hisham , Zec Zeljka , Hammontree Megan Ariana , Poyraz Altug Suleyman
Published: February 2020

The cathode dissolution is a known phenomenon for manganese dioxide (MnO2) based cathode materials in both aqueous and non-aqueous batteries. Upon battery discharge, reduced Mn3+ species disproportionate (2Mn3+→ Mn4+ + Mn2+) and Mn2+ dissolves into the electrolyte causing the loss of active material. While MnO2 is a promising cathode for rechargeable aqueous zinc ion batteries (ZIB) due to its availability and low toxicity, the electrochemical performance is limited during battery cycling due to the dissolution of the cathode. In this work, a homogeneous sol-gel SiO2 coatings with various thicknesses (0.5-5nm) on hydrothermally synthesized α-MnO2 nanorods are reported. In-depth characterization of SiO2 coated α-MnO2 are done by XRD, BET, XPS, TGA and SEM/TEM to analyze the surface of the silica coated α-MnO2 cathodes. The electrochemical performance of the SiO2 coated α-MnO2 cathodes are studied in two electrode zinc batteries at room temperatures using Zn metal anode and in 1 M ZnSO4 and 1 M TFSI electrolytes. The cathode dissolution is investigated by determining the total dissolved Mn content and characterization of the used electrodes. Electrochemical performances of SiO2 coated α-MnO2 are evaluated using Cyclic Voltammetry, EIS, and Galvanostatic Cycling tests. This study will further benefit all different battery types that have the same cathode dissolution problem.
Electrochemistry Research in the Stickney Lab: A Brief Summary of Dr. John Stickney's Past and Present Research
Authors: Howell Pauline , Stickney John Lewellen , Sisk Peter
Published: February 2020

Electrochemical atomic layer deposition (E-ALD) is a method deeply developed and furthered by the research of Dr. John Stickney. This talk will focus on a brief summary of his past research as well as present work conducted in this lab. E-ALD is a method where one component is deposited followed by another, keeping the conditions simple by operating at room temperature and using a three electrode flow cell.1 This type of deposition process adds control to the compound growth by limiting the amount of deposit to less than a monolayer per deposition cycle. A brief overview of the history of advances made in E-ALD will be given, leading into different materials that have been developed. Development of various CdTe deposition techniques will be discussed as well as the investigations into the deposition of germanene.2-4 Finally new work on GeSe will be discussed. Investigations into the effect of pH on the electrochemical deposition of Ge and Se were done. Deposition studies of Ge on Se-coated Au electrodes were carried out as well as Se on Ge-coated Au electrodes at different pHs in an effort to find conditions where a GeSe thin film can be deposited.

References

Stickney, J. L.; Villegas, I.; Suggs, D. W.; Gregory, B. W., Electrochemical Atomic Layer Epitaxy (ECALE). Abstr Pap Am Chem S
1991,
201, 289­Coll.

Zhang, X.; Shen, S.; Howell, P.; Cheng, W.; Mubeen, S.; Stickney, J. L., Journal of The Electrochemical Society
, 166 (5) H3249-H3256 (2019)

ACS Nano2017, 11, 9, 9481-948

Journal of The Electrochemical Society, 164 (7) D469-D477 (2017)
Nanoscale Materials Design and in Operando Visualization for High-Energy Ultra-Safe Batteries
Authors: Liu Nian
Published: February 2020

Zinc-based batteries have found applications in devices ranging from hearing aid to grid-scale batteries, due to their superior safety, high energy and low cost compared to Li-ion counterpart. However, zinc-based batteries, particularly zinc anodes, historically suffer from poor rechargeability. Since the launch of my lab at Georgia Tech in January 2017, we have focused on developing tools to uncover the important information about battery materials, as well as engineering battery materials at the nanoscale to solve their intrinsic problems. In this talk, I will present our recent progress in designing nanostructured materials to mitigate the reversibility problem of zinc anodes. Next, I will show our in-operando visualization of liquid product formation and dynamics in Zn-Br stationary battery. Finally, I will show examples of applying the above two research approaches in other battery systems.
(Invited) Characterizing Li-Ion Battery Extreme Fast Charging through in Situ Measurement of Temperature Distributions
Authors: Huang Shan , Wu Xianyang , Cavalheiro Gabriel M. , Du Xiaoniu , Liu Bangzhi , Du Zhijia , Zhang Guangsheng
Published: February 2020

Extreme fast charging (XFC) capability is important for wider adoption of battery electric vehicles (1). However, barriers to XFC still exist, including rapid heat generation and potential overheating of Li-ion batteries. Both life and safety of Li-ion batteries could be jeopardized by overheating (2-4). Moreover, temperature distributions in individual Li-ion cells would be non-uniform during XFC (5) due to low thermal conductivity of Li-ion cell materials (6, 7). The non-uniform temperature distribution could then lead to non-uniform degradation and underestimate of overheating by monitoring cell surface temperature. Indeed, a recent numerical modeling study (5) predicts overheating and non-uniform temperature distributions in Li-ion cells during XFC.

In this presentation we will report characterization of Li-ion cell behaviors during XFC through in situ measurement of temperature distributions. Figure 1 shows representative results of a 2Ah Li-ion cell during 1C, 3C, 5C and 7C constant current charging followed by 4.2V constant voltage charging. It can be seen that all temperatures increase much more rapidly during 7C charging than during 1C charging. It can be also seen that the difference between internal core temperature and external surface temperature during 7C charging is much larger than that during 1C charging. The results suggest overheating and obvious non-uniform temperature distributions during XFC even for a small Li-ion cell with capacity of 2 Ah and thickness of only 4 mm.

More results, including heat generation rate, voltage behaviors, effects of cooling, and degradation will be presented and discussed.

Figure 1. Rise of local temperatures in a 2 Ah Li-ion cell during 1C, 3C, 5C and 7C constant current charging followed by 4.2V constant voltage charging with forced convection air cooling

Figure 1