bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Lithium Plating – Understanding of a Very Complicated Phenomenon
Authors: Pawar Gorakh , Wang Xuefeng , Dufek Eric J. , Meng Shirley , Liaw Boryann
Published: February 2020

Lithium metal electrode (LME) poises as the best candidate for truly high-energy designs for rechargeable lithium batteries (RLB) when coupled with high-voltage, high-capacity cathode materials. To enable LME function well in such designs, very dense lithium (Li) deposition without dendrite growth is essential. To achieve this goal, acquiring fundamental understanding of Li nucleation and growth during deposition and the subsequent pathways toward stability during cycling at very negative, reducing potentials; is vital. It is well known that Li reacts with electrolyte to form solid electrolyte interphases (SEI). Putting the complicated SEI issues aside, understanding Li nucleation fundamentals is still very critical to ultimate Li deposition. Currently Li electrodeposition is limited by non-uniform behavior that leads to volume expansion due to pore generation, poor Li utilization (e.g. forming inactive or “dead” Li), and accelerated SEI formation and electrolyte decomposition due to increased interfacial area, just to name a few. The key question is, “Are these undesirable consequences come from the same origin or not?”

Here, multi-scale observations by cryogenic-transmission electron microscopy (cryo-TEM) and advanced reactive-molecular dynamics (r-MD) simulations were used to understand the kinetic progression of Li nucleation. The cryo-TEM imaging revealed that amorphous metal deposits can be obtained at room temperature with very slow deposition rates, traditionally only possible with very high quenching rates (e.g. >106 K s-1) on Li nucleation and reveals the transition from amorphous disordered states to crystalline ordered ones as a function of current density and deposition time. The r-MD simulations provide additional understanding of the driving forces and kinetic pathways for the nucleation and the associated amorphous-to-crystalline (disorder-order or second-order) phase transition. The incubation time for the phase transition varies with the Li canonical ensemble size, mass and energy transfer rate between an ensemble and the neighboring ones, and as a function of current density (i.e. Li deposition rate). It is important to note that this is the first time the r-MD was used to simulate kinetic pathway in a discrete manner with canonical ensembles to assess the impacts from the kinetic regime, which is very different from the conventional temporal or spatial averaging methods according to the statistical thermodynamics. Although the r-MD results were developed independently from cryo-TEM experiments, i.e. without any empirical correlation; there is a high degree of agreement with experimental observations.
Lifsi As Electrolyte Salt for Li-Ion Batteries in Full-Cell Configuration with Micron-Sized Silicon As Anode Material
Authors: Asheim Karina , Wagner Nils Peter , Andersen Hanne Flåten , Mæhlen Jan Petter , Svensson Ann Mari
Published: February 2020

Silicon is a promising anode material for Li-ion batteries1. Silicon’s ability to alloy with lithium results in a theoretical capacity ten times higher than that for graphite. However, since this high capacity involves several lithium ions per silicon atom, silicon will expand during lithiation and contract during delithiation. The volume changes causes the solid-electrolyte interphase (SEI) to crack, leading to continuous SEI formation. This eventually results in electronic insulation of the Si particles and large amounts of consumed lithium2. Hence, there is a need for an electrolyte composition that forms an SEI with increased ability to withstand the volume changes.

By changing the electrolyte salt, the reactions at the interphase between electrode and electrolyte also changes. Inspired by the work of Philippe et al.3, we have evaluated lithium bis(fluorosulfonyl)imide (LiFSI) as an alternative electrolyte salt to the commercial lithium hexafluorophosphate (LiPF6). Promising results were achieved with LiFSI as electrolyte salt in half-cells with micron-sized silicon as active material against circular Li foil as counter electrode.

The silicon based anodes used are made of 60 wt% Si (Silgrain®, e-Si 400, a commercially available battery grade silicon from Elkem), with an average particle size of 3 µm, 10 wt% graphite (Timcal, KS6L), 15 wt% carbon black (Timcal, C-Nergy C65, CB) and 15 wt% Na-CMC binder (Sigma Aldrich Mw ~90000). Slurries were cast onto dendritic copper foil and the electrodes were cycled in 2016 coin cells. The reference electrolyte composition is 1M LiFSI in EC:PC:DMC (1:1:3) + 5 wt% FEC and 1 wt% VC.

In this work, the performance of the silicon anodes are evaluated in full-cells with NMC as cathode. Performance in the reference electrolyte is compared to when LiPF6 is the electrolyte salt. In addition, the effect of increasing the LiFSI concentration is evaluated. The results include electrochemical performance and post mortem characterization of the silicon electrodes. The post mortem characterization includes XPS and cross sectional analysis to investigate how the electrolyte compositions affects the SEI. Cross sectional analysis is performed using focused ion beam in combination with scanning electron microscopy.

[1] J. Ling et al. Journal of the Electrochemical Society, 154 (3), A156-A161, 2007.

[2] H. Wu et al. Nano Today, 7, (5), 414-429, 2012.

[3] B. Philippe et al. Journal of the American Chemical Society, 135, 9829-9842, 2013.
High-Energy and Stable Li[Ni0.90Co0.05Mn0.05]O2 Cathode for Lithium-Ion Batteries through Microstructure Modification By Boron Doping
Authors: Park Kang-Joon , Kim Un-Hyuck , Kim Jae-Hyung , Sun Yang-Kook
Published: February 2020

Lithium-ion batteries (LIBs) are emerging as one of the most promising power sources for portable devices, as well as electric vehicles (EVs) and large energy storage systems (ESS), owing to their high energy density and excellent cycle life. However, the application of LIBs in EVs to reduce CO2 emissions in internal combustion engine vehicles (ICEVs) involves some critical technical challenges, such as the driving range, safety, and cost concerns due to the properties of LIBs.1-3 For this reason, research interests and industrial efforts have focused on developing low-cost, high-energy, and safe cathode materials, which are the main component determining LIB performance and cost. Transition metal layered oxides belonging to the LiNixCoyAlzO2 (NCA) or LiNixCoyMnzO2 (NCM) family, which can increase their intrinsic capacity (above 200 mAh g-1) by increasing Ni content, are emerging as promising new cathode materials.4 However, the intrinsic drawbacks of Ni-rich cathodes, such as low Li intercalation stability over extended cycles, should be improved. In this study, we present the first successful boron doping strategy for a Ni-rich cathode material with very high Ni content. For the boron doping, we used a simple method where only a small amount of B2O3 was added during the calcination process. In addition, the structural and morphological stability of the boron-doped Ni-rich NCM cathode material was investigated before and after testing to evaluate the improved electrochemical performance; specifically, the significantly enhanced cycle performance. Thus, we conclude that the boron doping strategy is an effective and simple way to mitigate the poor stability problem of Ni-rich cathode materials for high-energy and stable LIBs.

References

D.-W. Jun, C. S. Yoon, U.-H. Kim, Y.-K. Sun, Chem. Mater.
2017, 29, 5048.

J. H. Lee, C. S. Yoon, J.-Y. Hwang, S.-J. Kim, F. Maglia, P. Lamp, S.-T. Myung, Y.-K. Sun, Energy Environ. Sci.
2016, 9, 2152.

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.

K.-S. Lee, S.-T. Myung, K. Amine, H. Yashiro, Y.-K. Sun, J. Electrochem. Soc.
2007, 154, A971.
Novel Liquefied Gas Electrolytes for High Energy Density and Wide Temperature Range Li Based Batteries
Authors: Yang Yangyuchen , Davies Daniel Matthew , Yin Yijie , Fang Chengcheng , Lee Jungwoo Zema , Wang Xuefeng , Sablina Katya , Rustomji Cyrus Sam , Meng Ying Shirley
Published: February 2020

The application and performance of Li based batteries is often hindered by their electrolytes. These electrolytes have seen a relatively small amount of change since their commercialization and often limit both the energy density and low-temperature operation of devices. Here we use electrolytes based on solvent systems which are typically gaseous under standard conditions and show dendrite-free long-term cycling with high coulombic efficiencies of Li-metal anodes, as well as enhanced compatibility with high voltage cathodes. Importantly, the performance of the electrolyte is well maintained over a wide temperature range down to -60oC. Finally, we demonstrate full cell performance of systems utilizing the liquefied gas electrolytes in standard 18650 jelly-roll form factors with safety features unique from conventional Li-ion systems.
Reaction Mechanism of Li2MnO3 Electrodes in All-Solid-State Thin Film Batteries
Authors: Hikima Kazuhiro , Shimizu Keisuke , Suzuki Kota , Hirayama Masaaki , Tamura Kazuhisa , Kanno Ryoji
Published: February 2020

Lithium-rich layered rock-salt type Li2MnO3 is one of the most attractive cathode materials for lithium batteries because it achieved the high discharge capacities of 250−300 mAh g-1 after activation during the first cycling [1]. However, the structural deterioration in the following cycles at the cathode/liquid electrolyte interface leads to severe capacity fading. We reported that the Li2MnO3 films on solid system exhibit a high capacity of 250 mAh g–1 and better cycle stability, although liquid system showed severe capacity degradation [2]. To elucidate the activation process and high capacity phase contributing to high cycle stability, crystal structure changes at activation process were analyzed using the different initial structure of Li2MnO3. The initial structure was controlled by stacking solid electrolyte using two types of synthesis methods.

The Li2MnO3 electrode films were synthesized on SrRuO3/SrTiO3(111) substrates by pulsed laser deposition (PLD). Amorphous Li3PO4 as the solid electrolyte was synthesized by PLD and magnetron sputtering. Lithium metal was used as the negative electrode, respectively. The crystal structure changes at activation process were analyzed by in situ X-ray diffraction (XRD) measurements.

The Li2MnO3 structure had layered rock-salt type structure after stacking Li3PO4 by using PLD. On the other hand, in case of stacking by using magnetron sputtering, the Li2MnO3 changed disordered structure with the transition metal (TM) layer disordering of lithium and manganese ions in the honeycomb lattice. For the Li2MnO3 with layered rock-salt type structure, the discharge capacity increased continuously in the following cycles with persisting plateau region for several cycles. On the other hand, the Li2MnO3 with disordered structure showed about 300 mAh g–1 at the first cycle. The XRD intensity ratio of I
020/I
001 was zero after activation at both of initial structures [3]. Since the 020 peak arises from a superlattice structure by a honeycomb-type ordered arrangement of Li and Mn atoms in the TM layer, atomic arrangements in the TM layer transformed to a disordered state. This high capacity phase could contribute to its high capacity and cycle stability.

Acknowledgment: This work was supported by the Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2) of the New Energy and Industrial Technology Development Organization (NEDO).

References: [1] M. Sathiya et al., Nat. Mater., 2013, 12, 827-835.[2] K. Hikima et al., The 57th battery symposium in Japan, 2016, 2G22. [3] K. Hikima et al., The 58th battery symposium in Japan, 2017, 2C22.
Modulating the Surface Atomic Arrangement of Perovskite LaMnO3/C Towards Superior Electrocatalytic Activity and High Performance for Li-O2 Batteries.
Authors: Adjei Agyeman Daniel , Zheng Yongping , Park Mihui , Tamakloe Wilson , Cho Kyeongjae , Kang Yong-Mook
Published: February 2020

A composite of Lanthanum manganese oxide-carbon (LaMnO3/C) has been also synthesized by a facile electrospinning approach followed by controlled heat treatment, in which the carbon form a continuous conductive network connecting the electrocatalyst LaMnO3 nanoparticles together to facilitate good electrochemical performance. Based on a correlation between theoretical (DFT) and experimental analysis on the effect of the surface atomic arrangement, the electrocatalyst (Mn-terminated LaMnO3) with uniform Mn surface termination show favourable rechargeability, and good phase and morphology stability in lithium oxygen batteries compared to La rich surface termination. Excellent cycling performance is also demonstrated, in which the terminal voltage is higher than 2.4 V after 100 cycles at limited capacity of 1000 mAh g-1 (based on composite).

Figure 1
Enhanced Performances of Li, Mn Rich Cathode Using Polyacrylic Acid Binder in Lithium Ion Battery
Authors: Luo Hongze , Wen Lei
Published: February 2020

The lithium ion batteries have been a dominant power source for a wide range of portable electronic devices such as mobile phones, laptops and power tools since SONY commercialized the first lithium ion battery in 1991.

The development for higher capacity electrode material has been becoming more crucial due to expansion of lithium ion battery applications for advanced energy storage. The lithium and manganese rich cathode materials are one of the most investigated cathode materials among a variety of novel electrode materials with decent capacity. The lithium and manganese rich cathode oxides are considered as the solid solutions or nanocomposites between layered monoclinic Li2MnO3 and layered rhombohedral LiMO2 (M = Ni, Co, Mn, etc.). The complex 'layered-layered' structure has inherent shortcomings which include; large initial irreversible charge capacity, poor rate performance, capacity fade and voltage decay capacity fade upon prolonged cycling.

Many efforts have been devoted to overcome these drawbacks, such as fabrication of nano-sized materials, optimized preparation methods, crystal-plane tuning, doping and surface modification. Nonetheless, the development of this type composite cathode material for lithium ion battery is still the challenge for meeting future energy storage requirements.

Herein, the investigation on the performance of the lithium and manganese rich cathode using polyacrylic acid as binder is reported. The electrode using polyacrylic acid binder shows an enhanced performance compared to that of poly(vinylidene difluoride) based electrode.
Silicon Nanoparticles: Size and Morphology Effects in Lithium Ion Batteries
Authors: Lai Samson Yuxiu , Preston Thomas J , Skare Marte O , Klette Hallgeir , Knudsen Kenneth Dahl , Mæhlen Jan Petter , Koposov Alexey Y
Published: February 2020

Silicon in a form of nanoparticles has attracted a significant interest in the field of lithium-ion batteries, due to the enormous capability of lithium intake. While attracting substantial attention for next-generation lithium-ion batteries, the large volume changes due to lithiation/delithiation during charge/discharge significantly restrict wide application of those materials. To counteract the high-volume expansion associated with lithiation, silicon nanoparticles emerged as materials engineered to extend cycle life. However, correlating particle morphology, size and structure with performance in and lifetime of battery is still needed to make use of the diverse approaches toward predictable tunability of nanoparticle properties. For instance, various sources and various pathways for nanoparticles preparation of silicon lead to different battery performances resulting in large discrepancy of the results. Herein, we examine silicon nanoparticles prepared through pyrolysis of silane gas, compare them to conventional crystalline samples and correlate their morphological characteristics with the battery performance and cycle life. We demonstrate that temperature and silane concentration during synthesis influence the size and morphology of the silicon nanoparticles. For instance, relatively low temperatures typically produce a mixture of small and large round particles with smooth surfaces while relatively high temperatures produce particles with rougher surfaces with a narrower size distribution. These differences are correlated to crack formation and propagation in the electrode during formation cycles, as evidenced by post-mortem analysis. Different degradation pathways of the battery anodes resulting in different rates of capacity fading are demonstrated depending on the starting nanoparticle structure. In addition, in the present work we demonstrate the characterization of silicon nanoparticles with small angle neutron scattering (SANS) as a complementary method to conventional approaches for characterization such as microscopy, which allows the analysis of nanoparticles as an ensemble.
Discharging Batteries Using Maximum Power Point Tracking (MPPT) Algorithm
Authors: Shrestha Sujan , Dion Matt , Sholin Mark
Published: February 2020

In this work, we seek to answer the following question: “How long will a battery last if it is discharged at its maximum possible power?” Various primary battery chemistries (Zn-MnO2, Ag-AgO, Zn-air) and secondary battery chemistries (Ni-MH, Li-ion) are investigated. The maximum power point tracking (MPPT) algorithm, which has been used in photovoltaic devices so far, is applied to draw the maximum power possible from these batteries.

In the MPPT algorithm used here, a fixed magnitude of current is applied and the new value of power is calculated. If the new value of power is greater than the previous one, the current is varied in the same direction until the maximum power is reached. This algorithm is simple to implement and consumes low computing power. However, the magnitude of a current step should be optimized. If the current step is very small, the time taken to reach the maximum power will be too long. And if the current step is very large, there will be a large oscillation near the power maxima.

We present the effect of current steps in reaching the maximum power on batteries. The optimal current step is different from one battery to another. For fair comparison, the current steps are normalized to the discharge rate to achieve 1 C capacity. For rechargeable batteries, the effect of charging rates on the maximum power obtainable is also investigated.

The information obtained from this study can be a useful guide to designing a battery management system that gets the maximum performance out of any battery.

References

Selvan, P. Nair and Umayal, “A review of phot voltaic MPPT algorithms,” International Journal of Electrical and Computer Engineering, 6, 2016, 567-582.

A. B. Vieira and A. M. Mota, “Maximum power point tracker applied in batteries charging with PV panels,” 2008 IEEE International Symposium on Industrial Electronics, Cambridge, 2008, 202-207.

Kim, S. Mohan, J. B. Siegal and A. G. Stefanopoulou, “Maximum power estimation of lithium-ion batteries accounting for thermal and electrical constraints,” Proceedings of the ASME 2013 Dynamic Systems and Control Conference, California, 2013.
Lithium Sulfur Batteries with Modified Electrolytes Containing Ionic Liquids
Authors: Barghamadi Marzi , Djuandhi Lisa , Hollenkamp Anthony F. , Mahon Peter J. , Musameh Mustafa , Ruether Thomas , Sharma Neeraj , Best Adam Samuel
Published: February 2020

Lithium-sulfur (Li-S) batteries are a promising technology to reach a target of 500-700 Wh kg-1 as a replacement for current commercial Li-ion batteries in a number of sectors. They also offer lower environmental impact with reduced costs for the cathode materials. However, the level of currently achievable performance is still below expectations. This is due to a lack of understanding of the fundamental electrochemical processes and mitigating the undesired reactions during Li-S battery cycling. In particular the so-called redox shuttle effect, which arises from the solubility of polysulfides (PSs, Li2Sx) species, and their potential to reduce capacity retention of the battery. Modifying electrolytes with additives and new solvents change the solubility of these intermediates and potentially improve the cycling performance of the battery.

Herein, the effects of using LiNO3 as an additive as well as C4mpyr-based ionic liquid electrolyte on the performance of Li-S cells are analysed using electrochemical, in situ X-ray powder diffraction (XRD) and ex situ soft X-ray absorption spectroscopy (sXAS) techniques. Whilst both LiNO3 and C4mpyr-based IL participate in forming a protective stable SEI layer on the lithium anode, our studies have provided further evidence for the suppression of Li2S deposition on the electrodes when using LiNO3 salt as an additive in the electrolyte, leading to higher capacity and better capacity retention compared to the additive-free electrolyte. In addition, based on XRD data, different species of Li2Sx were detected during cycling of cells with organic and IL-based electrolytes, which indicates that different (electro)chemical reactions occur in these environments. Overall, cells with electrolytes containing ionic liquids and LiNO3 showed more stable cycling.
Investigation of Atomic Layer Deposited Al2O3 High Energy Nickel Cobalt Manganese Oxide Cathode Materials
Authors: Heiskanen Satu Kristiina , Jurng Sunhyung , Lucht Brett L.
Published: February 2020

High-Energy Nickel Cobalt Manganese Oxide (HED-NCM) is a state-of-art positive electrode material which achieves a high specific capacity (~250 mAh/g). Overall cycling life is limited by electrode degradation, stemming mainly from oxygen release as well as transition metal dissolution. To mitigate the latter problem, a thin layer of aluminum oxide (Al2O­3­) can be applied to the active material by atomic layer deposition (ALD) to form an artificial cathode-electrolyte interphase (CEI). Testing has shown that the Al2O3 coating improves overall reversible capacity, most notably at high temperature (40oC). However, effect of the Al2O3 on the CEI and SEI formed upon cycling has yet to be understood. The cycling performance and surface chemistry Al2O3 coated HED-NCM materials cycled at room temperature and 40°C were investigated via ATR-FT-IR and XPS spectroscopies, and ICP-MS after the first and 50th cycles. Overall, electrodes made with Al2O3 coated material had lower concentrations of polyethylene carbonate and fluorine species, and Al2O­3­ coating helps in preventing transition metal dissolution.
Effects of Thermal Exposure on the Structure Evolution of LiNi0.8Mn0.1Co0.1O2
Authors: Alvarado Judith , Wei Chenxi , Nordlund Dennis , Kroll Thomas , Sokaras Dimosthenis , Liu Yijin , Doeff Marca
Published: February 2020

High energy nickel-rich NMC (LiNixMnyCozO2; x+y+z≈1, x≥y+z) cathodes offer promising theoretical high capacity cell metrics. As the nickel content increases, the cathode exhibits a decrease in capacity retention, structural stability, and thermal stability. Herein, the thermal stability of chemically delithiated NMC-811 is investigated as a function of lithium content. A myriad of synchrotron characterization techniques are used to understand the role of the transition metals on structure stability at elevated temperatures. The in-situ heating experiments capture both chemical and morphological changes within the material that yield key particle size information on thermal stability. The bulk and surface sensitive techniques capture intermediate states between the transition metal 3d-oxygen 2p bonds at low temperatures, which inevitably can lead structural changes. This work demonstrates the importance in developing robust cathode materials for lithium ion batteries.
Advanced in-Situ Sensors for Smart Energy Storage
Authors: Fleming Joe
Published: February 2020

Lithium-ion technology is an increasing choice for battery powered systems, offering long-lasting, reliable and efficient energy storage. However, significant safety and performance challenges within the technology are still apparent. The current state of the art for monitoring cells performance is typically based on observing full cell voltage and occasional temperature sensor on the skin of a cell. Consequently, it is extremely difficult to track cells’ health and predict safety events within complex, especially high-performance, battery systems. Here we show the design and manufacturing methods of transforming normal cells into smart systems. Embedding reference electrodes, fibre optics and temperature sensors. This enables in-situ and operando data collection during cells’ real-life operations. The sensing methodologies and modification techniques developed in this work can be applied to all range of cells from small bespoke systems that are used within mobiles phones up to large scale battery modules and packs for electric vehicles and off-grid storage. We further demonstrate that our solution is compatible with long term operation and can be used to enhance the performance and safety of cells.
Tuning Interfacial Processes in Mn-Based Li-Ion Systems Though Vapor Phase Modification
Authors: Jarry Angelique , Hitz Emily , Ballard Jake , Margez Carine L , Park Joong Sun , Greszler Thomas A , Lin Chuan-Fu , Rubloff Gary W
Published: February 2020

Among the different rechargeable battery technologies available, Co/Ni/Mn-based Li-ion systems appear to be a leading contender for automotive applications as a result of their high specific energy. However, the high operating potential of this system is outside the thermodynamic stability window of standard organic carbonate-based electrolytes. This results in electrolyte oxidation with transition metal dissolution and gas formation at the electrode/electrolyte interface during cycling, which leads to severe loss of electrochemical performance. To address these challenges, many strategies are currently being investigated, ranging from the development of new electrodes and electrolytes to the improvement of commercial Li-ion systems by surface engineering of the interfaces.

In this work, we mitigate parasitic interfacial processes in start/stop batteries by atomic layer deposition (ALD). We develop an Al2O3 or LiPON conformal artificial SEI layer on LMO and LTO electrodes and study its effect on the Li-ion batteries failure modes with differential electrochemical mass spectroscopy (DEMS), X-ray Photoelectron Spectroscopy (XPS) and ICP measurements. The beneficial impact of the protection layer on the kinetics of the gassing, metal dissolution and associated chemical cross-talk was clearly identified. The presence of a protection layer at the LMO surface, in particular of a 10 nm LiPON conformal layer, mitigate the electrolyte oxidation at high voltage at 60°C with a significant reduction of the amount of H2 produced. The formation of metal complexes and subsequent poisoning of the SEI is also attenuated. Interestingly, counter intuitively, the ratio of the inorganic to organic components of the SEI is lowered by the presence of an inorganic protection layer. The correlation between the nature of the electrode protection layer, the electrode’s surface activity, and associated organic electrolyte oxidation pathways will be presented and discussed.

Acknowledgement

This work was supported by SAFT and as part of the Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science.
Toward a Metallic Silicon Anode for Practical Lithium-Ion Battery Applications
Authors: Ryu Jaegeon , Park Soojin
Published: February 2020

The current state-of-the-art batteries comprising graphite-based anodes are facing its performance limit for the use in automotive applications, thus urging to develop electroactive materials with high capacity and low operating potentials [1]. Si has shown great promise as a next-generation anode, meeting the above requirements in natural abundance. However, unavoidable large volume change upon lithium insertion/extraction causes particle fracture and disintegration of the electrode, resulting in fast degradation of battery along with poor electric conductivity being the main hurdle for fast-chargeable battery design [2]. Recently, interesting breakthroughs have been proposed principally in nanostructuring of Si, composite formation with conductive carbons and mechanically stable binders, which achieved long-term cycle stability and rate capability [3]. Yet, these approaches lead to lowering the electrode density, initial Coulombic efficiency and energy density of battery and thus utilizing the Si microparticles can be rather feasible toward a practical system while stress-driven particle degradation becomes more serious. The existing technologies have focused on coalescing the fractured particles, not preventing itself, and have not considered ionic diffusion of Li-ion across the microparticles as well as the electronic conduction.

Herein, we propose the material design concept of Si microparticles by integrating the chalcogen component into the bulk structure through a low temperature doping strategy. The low electric conductivity of intrinsic Si (~10-4 S m-1) with a near-insulator property undergoes a transition into the metallic state via this new method unlike other dopants of boron or phosphorous that only gives extra charge carriers without insulator-to-metal transition. In addition to electronic conduction, the chalcogen chains restrict the saturation of Si dangling bonding during recrystallization process of low temperature doping and create the internal channels inside the crystalline Si lattice. The incorporation of Li-ion channels further increases Li-ion diffusivity without any barriers in case of undoped Si microparticles due to the interfaces of lithium silicide and amorphous Si. Interestingly, chalcogen chains can sustain its internal structure with high flexibility and robustness which is directly corroborated by microscopy analysis, and lithium-induced intermediate can maintain the metallic nature at the interfaces that enhance the Li-ion diffusion over the cycles. Further, the porous but minimized surface area of Si structures increases the initial reversibility, extends the cycle life of battery up to hundreds of cycles with a high structural stability and facilitates fast-charging ability.

[1] A. S. Arico, P. Bruce, B. Scrosati, J. M. Tarascon, W. Van Schalkwijk, Nat. Mater. 2005, 4, 366.

[2] H. Wu, Y. Cui, Nano Today 2012, 7, 414.

[3] J. Ryu, T. Chen, T. Bok, G. Song, J. Ma, C. Hwang, L. Luo, H.-K. Song, J. Cho, C. Wang, S. Zhang, S. Park, Nat. Commun. 2018, 9, 2924
Modification of Electrochemical Behavior of Li-Rich Layered Oxide Cathode through Defect Consideration
Authors: Fung Kuan-Zong , Tsai Shu-Yi , Chang Li-Fu , Huang Bo-Yuan
Published: February 2020

Cathode materials formulated as xLi2MnO3-(1-x)LiMO2(M = Mn, Ni, Co, etc.) with layered structure received much attention due to their surprisingly high reversible capacity for Li-ion battery applications.[1,2] For better understanding of such high-capacity layered cathode, a systematic study on powder morphology, crystal structures and reaction mechanisms of Li1.2Mn0.54Ni0.13Co0.13O2 during electrochemical charge/discharge cycles were conducted. First, the capacity of Li-rich layered cathode powder was strongly affected by its particle size. To obtain various particle sizes of cathode powder, different powder synthesis routes have been adopted. By usng sol-gel process, particle size of Li1.2Mn0.54Ni0.13Co0.13O2 powder obtained is around 200 nm. On the other hand, Li1.2Mn0.54Ni0.13Co0.13O2 powder synthesized by solid-state reaction method gives particle size as coarse as 1.0μm. The initial discharge capacity of sol-gel processed Li-rich cathode was 250 mAh/g. After 40 cycles, the discharge capacity from the same cathode still shows a capacity as high as 205 mAh/g. However, for cathode powder from solid-state reaction, its initial capacity was 190 mAh/g that is 24% lower than that of sol-gel processed cathode. After 40 cycles, the capacity degraded to 137 mAh/g. The enhanced capacity of sol-gel processed Li-rich cathode is attributed to its enormous surface area and short Li diffusion distance provided for electrochemical reaction to take place. Although Li-rich layer-structured cathode material show a reversible capacity as high as 250 mAh/g at low rate, its electrochemical properties such as capacity loss at first cycle, rate capability and capacity fading still need to be examined and characterized. In this study, Li1.2Mn0.54Ni0.13Co0.13O2 were investigated. The TEM structural analysis shows that the evidence of spinel phase after cycling. It is believed that the transition from layered structure to spinel structure may also induce a large lattice distortion resulting in lattice breakdown and capacity fading. In additions, the phase transition may be caused by the redox reaction of transition metal ions through charging/discharging tests.
Hierarchical Yolk-Shell-Structured Metal Oxide/Carbon Hybrid Powders for Anodes in Li-Ion Batteris
Authors: Cho Jung Sang
Published: February 2020

Although yolk–shell structured transitional metal oxides (TMOs) with various compositions have been studied as anodes for lithium-ion batteries (LIBs) thus far, their long-term cycle properties are unsatisfactory in practical implementation. In order to solve this problem, compositing TMOs with C materials could be a general and effective strategy, but with the traditional synthetic process for the yolk–shell structure, it is difficult to prepare the yolk-shell structured TMO/C hybrid. In this study, we introduce a novel facile synthetic strategy for the yolk-shell structured TMO/C hybrid microspheres, for the first time. In particular, the yolk has a coral-like structure with interconnected mesopores. The synergetic effects of the coral-like yolk-shell structure with well-defined interconnected mesopores and a highly conductive C content result in advanced anodes with excellent Li+ ion storage properties. The detailed formation mechanism of the structure and its electrochemical properties as anodes for LIBs were investigated, in detail.
Electrochemical Property of Resorcinol-Formaldehyde Derived Monolithic Carbon Xerogel with Graphene Oxide Via One-Step, Template-Free and Catalyst-Free Hydrothermal Reaction
Authors: Yoon Tae-Ho , Huang Minhu , Park Han Yul
Published: February 2020

Monolithic carbon xerogel(MCX) with co-continuous porosity was prepared via one-step, template-free and catalyst-free hydrothermal polycondensation reaction with resorcinol(R) and formaldehyde(F), while mildly oxidized graphene oxide was also added to enhance the electrical conductivity. The gels were prepared in a pressurized Teflon mold at 100 °C for 6 h, followed by drying at 60 °C for 36 h and then 100 °C for 12 h, generating xerogels. The F/R and R/W ratios were optimized in the presence of the graphene oxide to afford co-continuous pore structure with interconnected carbon particles. Next, the xerogels were subjected to pyrolysis at 900 °C for 2 h and CO2 activation at 1000 °C for 2, 4 or 6 h. Among the gels, those with no crack generation upon 6 h CO2 activation were subjected to N2 sorption study and then electrochemical property measurement via cyclic voltammetry. In addition, these gels were also characterized by XRD, Raman, and SEM.
Preparation and Application of Li4Ti5O12 anode Material in Lithium-Ion Battery
Authors: Yang Chun-Chen
Published: February 2020

This research is focusing on preparing the Li4Ti5O12 anode material by a spray-drying method. Normally, we use graphite carbon as an anode material. The formation of dendrites on the graphite electrode surface may cause short circuits during high-rate charging or long-term cycling, and it possibly leads to thermal runaway of the battery. So, we use the Li4Ti5O12 anode material to solve its safety problem for lithium ion battery. However, the Li4Ti5O12 anode material cannot form a SEI film on the electrode surface; the electrolyte will decompose and even generate some gases (e.g., CO2, H2, CO, etc.). Therefore, the surface of the Li4Ti5O12 anode material is coated with aluminum phosphate (AlPO4); it can prevent that the Li4Ti5O12 anode material contact with the electrolyte directly. Moreover, LiAlPO4F solid ionic conductor might be formed on the surface to improve ionic conducting properties and reduce electrolyte decomposition. Systematical investigations including crystal structure analysis, micro-Raman spectroscopy, morphology characterization, and dynamic light scattering, were carried out. The electrochemical performance on half cells (2032 type coin cells) with Li/Li4Ti5O12 (LTO) electrode was tested. Electrochemical tests of the coin cells were conducted over the voltage range of 1.0–2.5V at a current density from 0.1C to 10C. The results of characterization properties demonstrated that LTO-P25-750oC sample possesses several notable results, such as: small particle size, spherical morphology, and better ionic conductivity, etc. The specific capacities of LTO-P25-750oC batteries at 0.1, 1, 5, and 10C were found to be 167, 160, 154, and 148 mAh g-1, respectively. In order to verify the performance in practical battery applications, LiNi0.5Mn1.5O4 (LNMO) material is chosen as the cathode material and assembled into LNMO/LTO full cell for performance study. It was found that the specific capacity was 136 mAh g-1 at a charge/discharge rate of 0.1 C/0.1 C. Moreover, the specific capacity at different rates (0.2/0.2C, 0.5C/0.5C, 1C/1C, 3C/3C, 5C/5C) were 123, 111, 96, 50, and 5 mAh g-1, respectively. It was found that the specific capacity still maintains around 122 mAh g-1 when the rate returned to the charge/discharge rate of 0.2C/0.2C. In conclusion, the our as-prepared LTO anode composite show excellent rate performance, good long-term cycling performance. It might be a potential anode material for Lithium-ion battery.

Keywords: Lithium titanium oxide (Li4Ti5O12), Titanium dioxide (TiO2, type P25), Spray-drying method, Lithium-ion battery (LIB), Aluminum phosphate (AlPO4)
Investigation of Unitary Degradation Cells for Li Batteries Diagnosis
Authors: Song Jinju , Lee Soyeon , Woo Jung-Je , Jang Il-Chan
Published: February 2020

Lithium ion Batteries (LIBs) are the most popular tools as energy storage systems for electric vehicles (EVs), large-scale energy storage system (ESS) owing to their high energy density, power properties. However, LIBs are complex systems which are not yet revealed completely for their degradation mechanism. In general, the loss of Lithium during cycling, depletion and decomposition of the electrolyte, structural collapse of active materials and resistance increase are the most probable reasons for the degradation of LIBs. To diagnose LIBs, we have focused to make a unitary degradation cell which has referred reason during cycling. Herein, we fabricate Li loss cell intentionally as specified value and figure out how different capacities between intended values and real value in cells. Furthermore, we investigate what different in electrochemical impedance between the fresh cell and the unitary degradation cell.
Preparation of High Capacity Cathode Material Li1.2Ni0.13Mn0.54Co0.13O2 Microspheres By Two-Step Spray-Dry Method for Lithium-Ion Batteries
Authors: Tang Chia-Ju , Yang Chun-Chen
Published: February 2020

As a promising cathode material for Li-ion batteries(LIBs), Li-rich layered oxide (donated as LLO) has been deeply concerned because of the superior performance and high energy density, however, it’s still suffering from structure deterioration during cycling and the irreversible removal of Li+ in the initial cycle. Micron-sized spherical powders are mainly used as cathode materials due to the high tap density and volumetric energy density, through the spray-drying process can prepare the ideal morphology for LIBs. In this work, hierarchical nano/micro-sphere Li1.2Ni0.13Mn0.54Co0.13O2 composites were synthesized by a two-step spray-dry method by using acetate materials and citric acid as a chelating agent in different molar ratios (transition metal ions (TM): citric acid = 3:1 / 3:2 / 3:3). Adding the CA chelating agent is beneficial to uniform distribution transition metal ions, better structural stability and electrochemical performance of the as-prepared lithium-rich materials. As the results, the morphology of Li1.2Ni0.13Mn0.54Co0.13O2 is spherical and without aggregation occurred. The LLO with hierarchical nano/micro-sphere plays an important role in improving the coulombic efficiency in the first cycle and also enhance the capacity retention after cycling. After 3 cycles activation from 2~4.8V, the discharge capacities of the Li-rich composite samples with 3:1, 3:2, 3:3 ratios displayed 254mAh/g, 280mAh/g, and 267mAh/g, respectively. It was found that the discharge capacity of the LLO composite with the ratio = 3:2 shows the best electrochemical performance among samples.

Keywords: Li-ion battery, Cathode material, Li-rich oxide, Spray-Dry, Hierarchical nano/micro-sphere
Characterisation and Initial Purification Studies of Recovered Electrode Material from EVS
Authors: Driscoll Laura Louise
Published: February 2020

Li-ion batteries have dominated the portable electronics’ market as the energy storage medium of choice for many years. With increasing concerns related to climate change and the increasing variety of applications in which these batteries can be used, an inevitable increase in demand for the raw materials required to assemble such batteries would be expected. This has led to increasing concern that the virgin materials may be depleted considerably by 2050 if demand continues to rise as predicted.[1]

With the government’s new environmental strategy pushing for the electrification of motor vehicles, with the aim of the majority vehicles on Britain’s roads to be electrically powered by 2030, methodologies must be developed in order to recycle these batteries once they reach end of life in order to reclaim the critical elements. Not only must these strategies be able to recover key elements such as Co and Li efficiently but they must also be able to deal with the wide variety of chemistries currently implemented within the electric vehicle market. The ultimate aim of the ReLiB project is to develop short route recycling methods which can reclaim the material for reuse in pristine batteries. This poster will discuss the initial characterisation and purification/reclamation of electrode materials recovered from batteries that would be destined to enter the recycling chain.

[1] A. Pehlken, S. Albach, T. Vogt, Is there a resource constraint related to lithium ion batteries in cars?, Int. J. Life Cycle Assess. 22 (2017) 40–53. doi:10.1007/s11367-015-0925-4.
Electrodeposition of Sn/SnO2 Composite Materials As Anode Material for Lithium Ion Batteries and the Micro-Mechanical Property
Authors: Chang Tso-Fu Mark , Tanabe Mana , Chen Chun-Yi , Sone Masato
Published: February 2020

Sn/SnO2 composite materials are promising anode materials in lithium ion battery. Electrodeposition with supercritical CO2(sc-CO2) emulsified electrolyte (EP-SCE) is an effective method in controlling morphology (Ni [1], Cu[2], and Co[3]) and crystallinity (ZnO [4]and TiO2 [5]) of electrodeposited materials. Sc-CO2 is CO2 at temperature and pressure above its critical point, which is 304.1 K and 7.38 MPa. CO2 is non-polar, therefore, the solubility of metal salts and electrical conductivity are both very low in sc-CO2. In order to conduct electrochemical reactions, surfactants are used to form emulsified electrolyte.

Co-deposition of SnO2 along with electrodeposition of metallic Sn can occur at the same time in a SnCl2 based electrolyte containing NO3
- ions [6]. The EP-SCE is expected to be effective in controlling concentration and properties of the SnO2 in metallic Sn film. In this study, Sn/SnO2 composite films are prepared by electrodeposition with supercritical CO2 (sc-CO2) emulsified electrolyte, and the mechanical properties in micro-scale are evaluated by compression test of micro-pilliars fabricated from the Sn/SnO2 composite film for practical applications.

Details of the high pressure electrochemical apparatus can be found in a previous study [1]. The electrolyte is composed of 0.22 M SnCl2, 0.015 M HCl and 0.31 M (NH4)3C6H5O7. The current density applied is varied from 2.8 to 17.3 mA/cm2. For the EP-SCE, the surfactant is C12H25(OCH2CH2)15OH. 0.2 vol.% of the surfactant is used to form the sc-CO2 emulsions. 20 vol.% of CO2 at 343 K and 15 MPa under agitation are used to ensure the formation of a stable emulsion. Electrodeposition without the sc-CO2 emulsions at ambient condition (CONV) was also conducted to be used as a comparison.

Surface morphology of the films prepared by EP-SCE were very smooth and compact, and the CONV films were porous. On the other hand, there is not much different in the average grain size between the EP-SCE and CONV films, which was about 50 μm for both the EP-SCE and CONV films. The oxygen content in the EP-SCE films can be up to 28.3 at.% by adjusting the electrodeposition parameters.

Micro-pillars with a 20×20 μm2 cross-section and a height at 40 μm were fabricated by focus ion beam from the deposited films. The yield stresses were ranged from 10 to 40 MPa when the current density changed.

Acknowledgment:

This work was supported by JST CREST Grant Number JPMJCR1433.

Reference:

[1] Electrochim. Acta 55 (2010) 6469-6475

[2] Thin Solid Films 529 (2013) 25-28

[3] J. Electrochem. Soc. 162 (2015) D423-D426

[4] J. Phys. Chem. C 117 (2013) 25596-25603

[5] Electrochem. Commun. 33 (2013) 68-71

[6] J. Alloys Compd. 403 (2005) 335-340
Melt-Processing of Electrodes for Lithium-Ion Batteries: A New Solvent-Free Approach
Authors: EL Khakani Soumia , Verdier Nina , Rynne Olivier , Ciszewski Dorian , Lepage David , Prébé Arnaud , Ayme-Perrot David , Badia Antonella , Dollé Mickael , Rochefort Dominic
Published: February 2020

Lithium-ion is currently the leading technology for electrochemical energy storage, especially in the transportation sector. The electrification of vehicles through the use of lithium-ion batteries (LiBs) is at the center of the world efforts to decrease atmospheric pollution by reducing CO2 emission. Due to the high efficiency of electrical motors, a net reduction in greenhouse gases is achieved upon electrification of vehicles even in areas where electricity is generated from fossil fuels. Yet, the rapidly growing production of LiB brings new concerns on the environmental cost of the technology. The analysis of a complete their life cycle, from mining precursors to recycling batteries at the end of their life, reveals that several steps of the cycle can be improved to further reduce the environmental footprint of lithium-ion batteries. It is in this context that our group got interested in developing alternative approached to electrode fabrication, a key aspect of LiB manufacturing. Currently, most of the electrode fabrication processes involves the use of organic solvents, typically N-methyl-2-pyrrolidone (or NMP), which is toxic and costly. As such, a considerable effort is spent during electrode fabrication to recuperate NMP vapors and prevent exposure to the workers and environment. Avoiding the use of any solvents during electrode fabrication would not only minimize the environmental impact but would also result into lower energy consumption.

This contribution presents a study of a new solvent-free melt process technique to LiB electrode fabrication through the use of elastomeric binders. The impact of formulation on active material dispersion, microscopic morphology, electronic percolation and porosity will be discussed. With such parameters optimized, the electrochemical response of composite electrodes based on LiFePO4 and Li4Ti5O12 active materials were characterized both individually and as full cells. The battery performance will be compared with PVDF-based electrodes made with a conventional approach.