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Large-scale production of vertically aligned single-walled carbon nanotubes (VA-SWCNTs) on metal foils promises to enable technological advancements in many fields, from functional composites to energy storage to thermal interfaces. In this work, we demonstrate growth of high-quality (G/D6, average diameters ∼ 2-3 nm, densities10

Graphic illustrating the chemical reactions that occur during sintering of LLZTO pellets up to 1100 °C.

A quantitative understanding of particle rigid body (RB) motion that inherently accompanies grain boundary (GB) diffusion is highly desirable to understand and control the dynamic interplay between coarsening and densification during solid state sintering. By computer simulation using a multi-phase-field approach, we analyze systematically the roles played by each of these processes at different stages of the shrinkage of the internal pore in a three-particle green body as a function of particle size as well as thermodynamic and kinetic factors of interfaces. We demonstrate that particle RB translation promotes both neck growth, and pore rounding and shrinkage. Moreover, the forces acting at GBs and pulling neighboring particles towards one another dynamically evolve as particles fuse. In contrast, particle RB rotation has no contribution to pore shrinkage. The translational force acting on an individual particle varies with not only its size, but also the number and sizes of its neighboring particles.

As lithium-ion battery (LIB) active material and cell manufacturing costs continue to drop with wider adoption of electric vehicles, electrode and cell processing costs remain too high in terms of reaching the ultimate U.S. Department of Energy (DOE) cell cost target of $80/kWh. This paper primarily covers major materials chemistry advancements made over the last 10 ​years ​at Oak Ridge National Laboratory (ORNL) in the space of advanced manufacturing science for LIBs with the aim of simultaneously meeting the ultimate cost target, 500 ​Wh/kg gravimetric energy density, 10-15-min fast charge times, and 1000 deep discharge cycles. Aqueous electrode processing with a variety of active anode and cathode materials is now a standard procedure at the DOE Battery Manufacturing R&D Facility at ORNL (BMF), including the latest processes developed for Ni-rich cathodes. New results on cobalt-free LiNi0.8Fe0.1Al0.1O2 (NFA 811) are also included and discussed in an electrode processing advantage context. In addition, colloidal processing advancements have been made for Si/C composite anodes for achieving >600 ​mA ​h/g capacities. Optimization of electrode coating parameters and drying protocols have been completed, which has elucidated how key processing variables need to be changed when parameters such as slurry solids loading, solvent type, and wet electrode thickness are changed. ORNL has also increased the line speeds at which thick cathodes can be processed using ultra-fast electron beam (EB) curing and substantially decreased formation cycling times to

Cobalt content in Li-ion battery cathodes has become a top concern due to its price volatility and limited source availability. Low-cobalt, Ni-rich active materials are promising candidates for next-generation cathodes due to their high capacities, and water-based processing of these materials can further reduce both cost and environmental impact. We systematically evaluated the water compatibility of four different LiNixMn1-x-yCoyO2 (NMC) powders with increasing nickel contents. Comprehensive characterization verified there is no major change to their bulk structures, and only slight surface modifications related to the removal of contaminant species. For the first time, we demonstrate that LiNi0.8Mn0.1Co0.1O2 (NMC 811) cathodes can be formulated in water and cycled 1000 times in full pouch cells with excellent capacity retention (~70% compared to ~76% for NMP-processed cells). When implemented in future battery production lines, aqueous processing of Ni-rich NMC will simultaneously enable cost reductions and higher cell energy densities.

Three-dimensional (3D) printed, hierarchically porous nickel molybdenum (NiMo) electrocatalysts were synthesized and evaluated in a flow-through configuration for the hydrogen evolution reaction (HER) in 1.0 M KOH(aq) in a simple electrochemical H-cell. 3D NiMo electrodes possess hierarchically porous structures because of the resol-based aerogel precursor, which generates superporous carbon aerogel as a catalyst support. Relative to a traditional planar electrode configuration, the flow-through configuration allowed efficient removal of the hydrogen bubbles from the catalyst surface, especially at high operating current densities, and significantly decreased the overpotentials required for HER. An analytical model that accounted for the electrokinetics of HER as well as the mass transport with or without the flow-through configuration was developed to quantitatively evaluate voltage losses associated with kinetic overpotentials and ohmic resistance due to bubble formation in the porous electrodes. The chemical composition, electrochemical surface area (ECSA), and roughness factor (RF) were also systematically studied to assess the electrocatalytic performance of the 3D printed, hierarchically porous NiMo electrodes. An ECSA of 25163 cm2 was obtained with the highly porous structures, and an average overpotential of 45 mV at 10 mA cm-2 was achieved over 24 h by using the flow-through configuration. The flow-through configuration evaluated in the simple H-cell achieved high electrochemical accessible surface areas for electrochemical reactions and provided useful information for adaption of the porous electrodes in flow cells.

Water-based processing for lithium-ion battery electrodes is attractive due to its lower manufacturing cost and smaller environmental impact. However, multiple challenges associated with aqueous cathode processing have hindered commercial adoption. Polymer binders are an important component of the electrode, and thus the choice of binders can alter electrode cycling performance significantly. In this work, four different water-based binder combinations are investigated for Ni-rich LiNi0.8Mn0.1Co0.1O2 (NMC811)-based cathodes, with a focus on the long-term electrochemical performance in practical-format full pouch cells. No additional pH-modulating additives were added to the aqueous cathode slurries, and no protective coatings were present on the cathode or aluminum current collector. Results are compared with the standard PVDF/NMP-based binder/solvent combination, used as a baseline. The influence of water-based binder type on slurry rheology and electrode microstructure are also discussed. All cells made by water-processing had worse rate performance compared to the baseline. However, the cell discharge capacity after 1000 U.S. Advanced Battery Consortium (USABC) cycles at C/3 charge/discharge rate was comparable to the baseline for two of the water-based cathode formulations (CMC & JSR, and LiPAA), demonstrating the potential viability of aqueous-processed Ni-rich cathodes at a commercial scale.

Simulations and experiments have revealed enormous transport rates through carbon nanotube (CNT) channels when a pressure gradient drives fluid flow, but comparatively little attention has been given to concentration‐driven transport despite its importance in many fields. Here, membranes are fabricated with a known number of single‐walled CNTs as fluid transport pathways to precisely quantify the diffusive flow through CNTs. Contrary to early experimental studies that assumed bulk or hindered diffusion, measurements in this work indicate that the permeability of small ions through single‐walled CNT channels is more than an order of magnitude higher than through the bulk. This flow enhancement scales with the ion free energy of transfer from bulk solutions to a nanoconfined, lower‐dielectric environment. Reported results suggest that CNT membranes can unlock dialysis processes with unprecedented efficiency., Concentration‐gradient driven diffusion rates of ions through single‐walled carbon nanotubes are shown to be up to 36 times faster than in bulk. This previously unrecognized flow enhancement scales with the ion free energy of transfer from bulk solutions to a nanoconfined, lower‐dielectric environment. Utilization of fast diffusion can greatly benefit fields ranging from hemodialysis to energy storage.

Most lithium-ion batteries still rely on intercalation-type graphite materials for anodes, and the formation process for them typically takes several days or even more to provide a stable solid electrolyte interphase (SEI). The slow formation step results in lower LIB production rates, requires a large number of battery cyclers, and constitutes the second highest cost during battery manufacturing. In an effort to decrease the high manufacturing cost associated with long formation times, we studied five different formation protocols in nickel-rich LiNi0.8Mn0.1Co0.1O2 (NMC811)/graphite cells where the total formation time varied from 10 to 86 h. Electrochemical characterization and post mortem analysis show that very long formation time do not necessarily improve long-term performance while very short formation protocols result in lithium plating and poorer electrochemical performance. We find the optimum formation cycling protocol is intermediate in length to minimize impedance growth, improve capacity retention, and avoid lithium plating.

Aqueous processing of lithium nickel manganese cobalt oxide (LiNi0.5Mn0.3Co0.2O2, NMC 532) cathodes was investigated by incorporating carbon nanotubes (CNTs) as the conductive additive. Morphology observation showed CNTs evenly disperse across the electrode, uniformly covering each primary particle, and form three-dimensional electronic pathways. A resistance measurement indicated the CNTs can improve the electronic conductivity of the composite electrode by an order of magnitude compared to carbon black. CNTs based electrodes showed higher rate performance, lower hysteresis, and better cycling performance with 99.4% capacity retention after 200 cycles in full pouch cells compared to 94.6% for carbon black based electrode. Meanwhile, the content of active materials in the electrode was increased from 90 wt% to 96 wt% and the energy density was increased by 11.7%. This research demonstrates an effective combined approach for achieving aqueous processed cathodes with enhanced durability while simultaneously achieving higher energy density by reducing the content of inactive components.

Increasing lithium-ion battery gravimetric energy density to > 300 Wh/kg, while simultaneously meeting a cost target of $80/kWh, is of paramount importance to increasing the driving range and affordability of electric vehicles. One way to address this goal is to reduce inactive components by increasing electrode areal capacities, but conventional thick electrode designs typically perform poorly at high discharge rates due to Li+ mass transport limitations. Here we compare the rate capability and cycle life of NMC 532/graphite pouch cells made with five different thick cathode and anode designs paired together in 25 combinations. We find that using different particle sizes to structure both the cathode and anode architectures in two-layer configurations results in a 2X capacity improvement over the worst-performing combination at high discharge rates (97 vs. 46 mAh/g at 2C). These different cathode/anode designs also translate to different cycle life performance, with many cells cycled at C/2 achieving ∼80% capacity retention after 1000 cycles, and cells cycled at 2C showing different degrees of capacity fade. Overall, these results demonstrate that simple, scalable changes in electrode design can significantly improve the performance of thick electrodes for high energy density batteries.

Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by ~70% from 2008 to 2015, the current battery pack cost ($268/kWh in 2015) is still >2 times what the USABC targets ($125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.

Aqueous processing of thick electrodes for Li-ion cells promises to increase energy density due to increased volume fraction of active materials, and to reduce cost due to the elimination of the toxic solvents. This work reports the processing and characterization of aqueous processed electrodes with high areal loading and associated full pouch cell performance. Cracking of the electrode coatings becomes a critical issue for aqueous processing of the positive electrode as areal loading increases above 20–25 mg/cm 2 (∼4 mAh/cm 2 ). Crack initiation and propagation, which was observed during drying via optical microscopy, is related to the build-up of capillary pressure during the drying process. The surface tension of water was reduced by the addition of isopropyl alcohol (IPA), which led to improved wettability and decreased capillary pressure during drying. The critical thickness (areal loading) without cracking increased gradually with increasing IPA content. The electrochemical performance was evaluated in pouch cells. Electrodes processed with water/IPA (80/20 wt%) mixture exhibited good structural integrity with good rate performance and cycling performance.

Garnet-type solid electrolytes, such as Li6.4La3Zr1.4Ta0.6O12 (LLZTO), are promising materials for solid-state batteries, but processing remains a challenge, in part due to the high sintering temperature required for densification. This temperature can be lowered by decreasing the initial particle size via solvent-assisted ball milling, but the relationship between solvent choice, particle properties, sintering behavior, and ionic conductivity is not well understood. In this work, we systematically explore these parameters, showing that milling in commonly used protic solvents, such as alcohols, effectively decreases the particle size but results in lithium loss (through Li+/H+ exchange) that leads to poor sintering. By contrast, milling in aprotic solvents with surfactant reduces the particle size to ~220 nm without lithium loss, enabling the fabrication of dense samples (5.1 g/cm3) with good ionic conductivity (0.43 mS/cm at 25 °C) at a lower sintering temperature (1000 °C). We compare ionic conductivities and activation energies for samples prepared with different particle sizes and sintering temperatures and use multiphase-field simulations to identify the mass transport and microstructural mechanisms responsible for the observed sintering dependence on particle size. These results further clarify the relationship between processing parameters and performance and represent important progress toward overcoming fabrication challenges for these materials.

With the realization of the global impact of waste carbon on the atmosphere, coupled with a clear and growing demand for abundant electricity, there are both environmental and economic driving forces for capturing and electrochemically converting carbon dioxide (CO2) into high value hydrocarbon products. While much of the recent focus in this area has been driven by catalyst discovery, there is a lack of understanding on how the partnership of the catalyst and the reactor can be optimized for product selectivity and overall performance. The development of novel and optimized electrochemical reactors for this reaction is critically important; to address this gap, we report the use of advanced materials and manufacturing capabilities to design and construct electrocatalysts and electrochemical reactors for CO2 reduction. We report that by 3D printing catalysts and reactors, we can affect catalyst morphology, environment and reaction conditions, and thereby improve performance of Ag and Cu catalysts for electrochemical CO2 reduction. Our work at LLNL demonstrates our ability to leverage 3D printing and advanced manufacturing as tools to help study and improve catalyst activity, product faradaic efficiency, and overall energy efficiency.

All-solid-state batteries offer great promise for safer and higher-energy-density storage compared to conventional liquid-based Li-ion batteries. However, their practical use is hindered by high resistance caused by heterogeneity of structure and chemistry at the solid-state interfaces. To overcome these challenges, atomic-scale visualization of the interfaces and a detailed understanding of the correlation between interfacial structure, chemistry and processing conditions is critical. In this work, we use a combination of first-principles simulation and high-resolution scanning transmission electron microscopy with spatially-resolved electron energy loss spectroscopy to probe complex interfacial structures and chemistry in all-solid-state lithium batteries. We will further address how the processing conditions to prepare the interfaces will affects their structures, local chemistries and Li-ion conductivity through these interfaces. This work of was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Solid-state batteries promise substantially higher energy densities and improved safety compared to traditional Li-ion batteries due to the replacement of flammable liquid electrolyte with solid-state materials. These advantages make them excellent candidates for next generation energy storage, but many processing and performance challenges must first be addressed. While several different types of solid-state electrolytes have been proposed, inorganic materials such as Li6.4La3Zr1.4Ta0.6O12 (LLZTO) have attracted much interest due to their high ionic conductivities and good mechanical and electrochemical properties. However, these materials are brittle and prone to large interfacial resistance, and many of the current fabrication techniques are difficult to scale up for manufacturing. 3D printing is an excellent tool to help solve some of these challenges, since it is scalable and capable of creating tailored architectures and compositions that can facilitate Li+ transport and reduce interfacial resistance. We report the development and optimization of ink formulations and processing conditions for 3D printed solid-state electrolytes. Since the electrolyte must be sintered after printing to densify the structure and achieve good ionic conductivity, initial particle size is an important consideration for both ink rheology and sintering success. We investigated the effect of milling solvent on particle size and lithium loss, both of which can affect the final ionic conductivity. In addition, while samples are traditionally mechanically pressed to aid densification during sintering, this technique cannot be used with printed architectures. Therefore, we explored other strategies to facilitate densification, including incorporating additional materials to act as sintering aids and optimizing ink composition and active material volume fraction. Samples were analyzed by SEM, XRD, and EIS to correlate processing and sintering conditions with electrochemical performance. Our results demonstrate significant progress toward 3D printing architected solid-state electrolytes with good ionic conductivity for high-energy-density solid-state batteries.

Ni-rich, or low-Co, layered active materials are promising candidates for next-generation cathodes for lithium-ion batteries. However, these materials present processing and performance challenges such as compatibility with water during aqueous electrode formulation, unoptimized SEI/CEI formation conditions during cell assembly, and unstable capacity fade when cycled to upper cutoff voltages above 4.3 V vs. Li/Li+. The DOE Battery Manufacturing R&D Facility at ORNL (BMF) has recently moved towards low-Co-containing and high-energy LiNi0.8Mn0.1Co0.1O2 (NMC 811) as a new internal cathode baseline and away from LiNi0.5Mn0.3Co0.2O2 NMC 532 for conducting cathode water stability and formation protocol studies. These XRD, Raman spectroscopy, XPS, and TEM studies verified that there was no change in bulk structure of the NMC 811 with long-term water exposure, and only small changes in the surface chemistry. Capacity retention under 0.33C/-0.33C USABC long-term cycling for NMC 811 aqueous-processed single-layer pouch cells was obtained and compared to: 1) the NMP/PVDF processed standard; and 2) NMC 811 exposed to water for 4 hours before processing with the standard NMP/PVDF formulation. The water exposed NMC 811 processed in NMP showed a similar capacity fade to the aqueous processed case. However, all three cases showed excellent capacity retention through 600 cycles, and the aqueous processed cells and NMP processed cells exhibited ~75% and ~80% capacity retention through 1000 cycles, respectively. It was also observed that the differences in capacity fade for all three cases occur within the first ~100 cycles, and the capacity fade slopes were similar from that point on. It is thought that this slight difference in early capacity retention is due to surface chemistry changes of the NMC 811 during aqueous processing and could be remedied with shorter mixing times or a surface protective coating. To decrease the high manufacturing cost associated with long formation times for low-Co cathodes, five different formation protocols were studied using graphite anodes where the total formation time varied from 10 to 86 h. Electrochemical characterization and post mortem analysis showed that longer formation times do not necessarily improve long-term performance while extremely short formation protocols result in lithium plating and poorer electrochemical performance. It was found that the optimum formation protocol is intermediate in length to minimize impedance growth, improve capacity retention, and avoid lithium plating. This presentation will focus on recent ORNL advancements in these areas, where aqueous processing conditions (mixing times, water exposure, binder type, etc.) and fast formation protocols are being developed for NMC 811 and that will be extended to other low-Co and Co-free cathodes.

Thick electrodes have attracted considerable interest due to their potential role in achieving high energy density Li-ion batteries for electric vehicle applications. Incorporating thick electrodes eliminates many of the inactive separator and current collector layers that add cost, weight, and volume to the battery. However, mass transport of Li ions becomes a limiting factor at these dimensions and leads to poor rate capability at high charge and discharge rates. Different electrode architectures have been proposed to facilitate Li ion transport throughout the entirety of the electrodes, but the connection between structure and performance remains unclear. We used two different active material particle sizes to create thick anodes and cathodes (~4 mAh/cm2) with different structures and pore size distributions to determine the effect of architecture on electrochemical performance. Seven graphite anodes and seven NMC 532 cathodes were coated in various single- and double-layer configurations and assembled into single-layer pouch cells in forty-nine different cathode/anode combinations. These cells were then subjected to charge and discharge rate performance testing. We found that both particle size and structural arrangement have significant impacts on the resulting rate performance. Mercury porosimetry was performed on all electrodes to help correlate pore size distribution with performance. In addition, the best- and worst-performing cells were selected for post-mortem analysis to further understand the nature of the observed electrochemical differences. Our results demonstrate that the rate performance of thick electrodes can be improved by altering the electrode architecture. More precise control over the structure could lead to further improvements and enable the implementation of thick electrode Li-ion battery designs for cheaper, long-range electric vehicles. Figure 1

Fabrication plays a key role in determining the unique electrical, optical, and catalytic properties of metal nanowires. Here we present a bipolar electrochemical method for dynamically monitoring and controlling the rate of single metal nanowire growth in situ without a direct electrical connection. Solutions of a metal precursor and a reducing agent are placed on either side of a silica nanochannel, and a pair of electrodes is used to apply a tunable electric potential across the channel. Metal nanowire growth is initiated by chemical reduction when the two solutions meet and continues until the nanochannel is blocked by the formation of a short metal wire segment. Further growth is driven by a bipolar electrochemical mechanism which enables the reduction of metal precursor ions at one end of the nanowire and the oxidation of the reducing agent at the other. The growth rate is monitored in real time by simultaneously recording both the faradaic current and optical microscope video and can be adjusted accordingly by changing the applied electric potential. The resulting nanowire is solid, electrically insulated, and can be used as a bipolar nanoelectrode. This technique can be extended to other electrochemical systems, as well, and provides a confined reaction space for studying the dynamics of any process that can be optically or electrically monitored.

Insufficient energy density is one of the barriers for widespread application of lithium-ion batteries (LIBs). Increasing energy density relies on developing novel active materials with higher energy density and/or increasing the active material ratio via electrode engineering [1]. One natural strategy is to increase the energy density by increasing the electrode thickness, which reduces the fraction of some inactive components such as current collectors and separators. However, thick electrodes suffer from electrolyte depletion under high discharge rates and low power density. As a result, electrodes are divided into two categories—thin electrodes (ca. 50 µm) for high power application and thick electrode (> 100 µm) for high energy application [2]. This work reports a design in thick electrodes with 3D micro-structures enabled by laser processing, which minimizes the electrode tortuosity and improves the lithium ion diffusion kinetics. This novel design enables high energy and high power densities for LIBs. References: [1] Z. Du, D.L. Wood, C. Daniel, S. Kalnaus, J. Li, Journal of Applied Electrochemistry 47 (3), (2017) 405-415 [2] P. Smyrek, J. Proll, H. J. Seifert, and W. Pfleging, Journal of the Electrochemical Society, 163 (2), (2016) A19-26. Acknowledgements This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office(VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy). This work at Karlsruhe Institute of Technology (KIT) received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 644971. Finally, the support for laser materials processing by the Karlsruhe Nano Micro Facility (KNMF, http://www.knmf.kit.edu/) a Helmholtz research infrastructure at KIT is gratefully acknowledged.

Abstract Aqueous processing of Li-ion battery electrodes promises to reduce cost due to the elimination of the toxic solvent N-Methyl-2-pyrrolidone (NMP) [1]. It has been reported that good rate performance and cycling performance can be achieved by aqueous processing of lithium nickel manganese cobalt oxides (LiNi0.5Mn0.3Co0.2O2, NMC532) at ~2 mAh/cm2 loading [2]. To further increase the energy density of Li-ion cells, the loading needs to be increased to at least ~4 mAh/cm2 [3]. However, loading increases to this level using aqueous processing introduce critical cracking issues leading to poor performance [4]. This work reports the importance of surface tension control in the preparation of slurries for coating manufacturing with high areal loadings. Crack initiation and propagation associated with the build-up of capillary pressure during the drying process will be discussed. The surface tension of the slurry is reduced by the addition of another solvent, which leads to improved wettability and decreased capillary pressure during drying. The critical thickness (areal loading) without cracking increases gradually with decreasing surface tension. The electrochemical performance of pouch cells will also be discussed. Acknowledgements This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office(VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy). References: [1] D. L. Wood, J. Li and C. Daniel, J. Power Sources 275 (2015) 234. [2] J. Li, D. Mohanty, C. Daniel, and D. L. Wood III, Aqueous Processing of LiNi0.5Mn0.3Co0.2O2 Composite Cathodes for Lithium-Ion Batteries, 225th ECS meeting, May 11-15, 2014. [3] Z. Du, D.L. Wood, C. Daniel, S. Kalnaus, J. Li, J. Applied Electrochemistry 47 (2017) 405. [4] Z. Du, K.M. Rollag, J. Li, S.J. An, M. Wood, Y. Sheng, P.P. Mukherjee, C. Daniel, D.L. Wood III, Enabling aqueous processing for crack-free thick electrodes, J. Power Sources, In press.

Evaluation of electrode coatings using in-line non-destructive techniques and understanding the effect of electrode manufacturing defects on lithium-ion battery (LIB) performance is vital to the quality control process and key to reduce the scrap rate during cell manufacturing. In this regard, it is vital to quantify the effect of various defects that are generated during electrode coating process (Layered NMC532 cathode in this study) on LIB performance. To this end, we demonstrate defect detection and porosity measurement using IR thermography and thickness measurement using a laser technique at high line speeds. We show the comparative effects of different defects that were intentionally generated such as agglomeration, pinholes, and non-uniform coating on LIB performance in full coin cells and large pouch cells. The results show that the electrodes with more coated/non-coated interfaces had greater capacity fade than baseline electrodes at high current densities and that pinholes and agglomerates did not affect the performance adversely. In conclusion, these types of characterization of control samples shows the importance of monitoring and early detection of the electrode defects during the coating process for minimization of cell rejection rates prior to fabrication and formation cycling. Acknowledgement: This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy).

Despite recent advances in lithium-ion battery technology, further energy density improvements and cost reductions are necessary to achieve widespread adoption of electric vehicles. Nickel-rich formulations of lithium nickel manganese cobalt oxide (NMC) have been developed as promising high-energy, high-voltage cathode materials capable of significantly increasing the energy density of lithium-ion batteries. Aqueous processing of these cathodes offers significant environmental benefits and lower production expenses compared to traditional processing using N-methylpyrrolidone (NMP). However, Ni-rich NMC materials can react with water during electrode preparation, and with electrolyte during battery assembly and cycling, resulting in metal leaching that can cause structural changes and performance degradation. We investigated the effect of aqueous processing on the structure and electrochemical behavior of these cathode materials by exposing four NMC powders with varying nickel contents (NMC 333, NMC 532, NMC 622, NMC 811) to water and electrolyte for different time durations meant to simulate electrode processing and battery assembly conditions. The resulting metal dissolution was then measured using inductively coupled plasma mass spectrometry (ICP-MS). Since the pH of aqueous slurries can differ depending on composition, and pH variation may lead to additional reactions, the effect of pH was also explored. We found that lithium dissolution increases with increasing nickel content at all pH values, and slurries made with all four powders become basic during typical processing times. Dissolution of Ni, Mn, and Co in water was minimal for all formulations. In order to gain a better fundamental understanding of the structural changes taking place during these reactions, a subset of the NMC powders was characterized by SEM and X-ray photoelectron spectroscopy (XPS) before and after exposure to water and electrolyte. In addition, the effect of aqueous processing on battery performance was evaluated by comparing the rate performance of pouch cells made using cathodes processed with different water exposure durations. Correlating processing conditions with performance could lead to the design of new approaches to mitigate metal leaching from Ni-rich NMC materials and enable the use of these cathodes for high energy density lithium-ion batteries. Acknowledgment This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy). Figure 1

The development of nickel-rich NMC cathodes (LiNixMnyCo1-x-yO2 with x > 0.5) is among the most promising routes to deliver lithium-ion cells with energy densities exceeding 250 Wh/kg. Achieving this ambitious target will require cycling cells to higher voltage (>4.35 V) and developing new strategies to mitigate undesirable side-reactions like electrolyte oxidation and cathode surface reconstruction. Since the cathode has long been considered the limiting factor in developing high-energy, high-voltage cells, the impact of the graphite anode has been largely ignored. In this contribution, we show that the choice of graphite significantly impacts both the rate capability and long-term cycling stability of cells with Ni-rich NMC cathodes. Six commercially-available natural and synthetic graphites were tested in full cells with NMC 811 cathodes (LiNi0.8Mn0.1Co0.1O2). The variations in cell performance were correlated with the chemical, morphological, and mechanical properties of the different graphite anodes. Surface chemistry was systematically investigated using X-ray photoelectron spectroscopy (XPS), while electron microscopy and mercury porosimetry were used to understand how electrode structure impacts the electrochemical performance. Peel tests were used to identify the importance of mechanical adhesion of different graphites to the current collector. In-depth electrochemical studies including impedance spectroscopy further shed light on the nature of capacity fading. Our study illustrates the important role of the graphite anode in developing high-energy, high-voltage Li-ion batteries. This work serves as a guide to select the appropriate graphite to optimize performance of Ni-rich NMC cells. Acknowledgement: This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy).

We present the preparation, characterization, and analytical application of silica nanochannels in the size range of 5-100 nm. These cylindrical-shaped nanochannels are prepared using a simple laser-assisted mechanical pulling process, followed by partial enclosure into a glass micropipet. The nanochannels are characterized using a combination of optical microscopy, scanning electron microscopy (SEM), and resistance measurements in an electrolyte solution. The SEM results show that the nanochannel has circular geometry at the orifice. Ohmic response has been obtained from current-voltage measurements in KCl solutions using a silica nanochannel as small as 9 nm in diameter. These nanochannels have been utilized to sense single 40 nm polystyrene nanoparticles. A linear response has been observed between the detection rate and the concentration of nanoparticles in the range of 0-25 nM. The silica nanochannels have also been applied to the study of molecular transport of double-stranded DNA. Electroosmosis-driven molecular translocation has been observed for genomic-length lambda-DNA through a 9 nm nanochannel in a 3 M KCl solution.