bluuebunny/crossref_metadata_2025 huggingface dataset:
High Lithium Storage Properties of MnFe2O4 Mesoporous Microspheres As an Anode Material for Li-Ion Batteries
Authors: Sunkara Satyendar
Published: February 2020

Lithium-ion batteries (LIBs) have attracted tremendous attention because of their sustai-nability, high energy density, long cycle life and environmental benignity. Apart from these, LIBs have great potential applications in electric vehicles, potable electronics, solar and wind-based electricity generation systems and renewable energy storage. LIBs became prominent power sources as the non-renewable fossil-fuels result in massive air pollution and depleting very fast. Considering the scarcity, environmental benignity and cost, it is important to develop low cost, high abundance and eco-friendly electrode materials for LIBs which can deliver high energy and power densities with long cycle lives. Manganese ferrite, MnFe2O4 is one of the binary metal oxides and belongs to iron spinel which has been studied widely for its application in drug delivery supercapacitors and in magnetic devices. However, to the best of our knowledge, there have been only a few studies on the application of MnFe2O4 as anode materials for LIBs although it possesses a high theoretical capacity of 930 mA g-1, which is much higher than that of commercial graphite anode. But MnFe2O4 suffers from poor cycling stability because of the large volume changes during lithiation/delithiation. Here, mesoporous microspheres of MnFe2O4 have been successfully synthesized by a facile method followed by a post heat treatment. The mesoporous MnFe2O4 electrodes exhibit high reversible capacity of 733 mA h g-1 after 50 cycles at the current density of 100 mA g-1 indicating the excellent cycling stability. The cell delivered discharge capacities of 1371, 1008, 876, 625, 523, 380 mA h g−1 at current densities of 100, 200, 400, 800, 1000, 1500 mA g−1, respectively. Even at a high current density of 1000 mA g−1, the electrode could deliver a discharge capacity of 523 mA h g−1, which is much higher than the theoretical capacity of graphite. Interestingly, even after stepwise increment in the current densities while measuring the rate capability, the electrode retains a capacity of 812 mA h g−1 when the current rate reverts back to 100 mA g−1.  We believe that such good performance results from the mesoporous nature of MnFe2O4 microspheres, which can substantially absorb large volume changes due during Li+ insertion/extraction.

 

Figure 1
Parsing the Battery Lithium Supply Chain: A Quantitative as well as a Qualitative View of Lithium Mining, Refining, and its Use in Fabricating Storage Battery Components
Authors: Lifton Jack P
Published: February 2020

The identification of mineable deposits of lithium in brines; hard rock; or clay is just the beginning of a process to complete a supply chain for storage battery components that is  strictly controlled by two comprehensive factors: 1, The economics of the best available technologies; and 2, The geopolitics of the regions and nations in which the deposits are located. The  broad spread of the use of EVs, HEVs, and PHEVs may well depend on the fact that the best manufacturing technologies for them are located in East Asia while the largest deposits of the necessary lithium and other elements  are located in South America; Africa; and Australia.

Lithium itself is a relatively cheap commodity today. What will be the effect of a global demand exceeding supply in the near term and in the long term. Can mining and refining keep up with government subsidized demand?
Understanding the Evolution of the Li-Rich Antifluorite Li5FeO4 upon Electrochemical Delithiation
Authors: Zhan Chun , Lu Jun , Amine Khalil
Published: February 2020

In order to boost the capacity of the lithium ion battery, cathode materials that can cycle with more than one lithium (Li) ion per transition metal (LM) ion are intensively investigated. The antifluorite family of Li8O4 (4Li2O unit cells) is an interesting structure to host high Li/TM ratio since the transition metal ions can substitute part of the tetrahedral Li ions the structure. A representative material is the Li5FeO4 (LFO), with one Fe3+ ion replacing one tetrahedral Li+ion and creating two vacancies.  This material is capable of providing 5 Li/Fe or a capacity at about 867mAh/g in theory. Initial studies of LFO have yielded intriguing results that more than 4Li ions can be extracted at two plateaus at about 3.5 and 4.0V, with capacity higher than 700mAh/g. This super high delithiation capacity makes LFO a promising cathode material for the high energy Li-ion batteries. However, in the first discharge the plateaus decrease to 2.2V and 1.3V with a capacity of about 300mAh/g. In the following cycles, the capacity fades rapidly and the plateaus higher than 3V can’t be recovered. The cycle behavior of LFO shows that the deliathiation reaction of the LFO with the removal of over 4 Li ions is not reversible in conventional Li ion batteries.

In order to fulfill the reversible charge-discharge of the LFO,better understanding of the delithation reaction of LFO is required. In this work a series of comprehensive in-situ characterizations of the LFO electrode during the first charge were performed to understand the crystal structure, valance and bonding as well as the electronic structure evolution of LFO upon the Li removal. These studies indicate that the first charging of LFO can be divided into two stages. Stage I is a two-phase reaction in the first charging plateau, where the antiflorite LFO converts to pseudo-cubic Li3FeO4 (Li5FeO4→2Li++2e+Li3FeO4), and the oxidation state change of Fe and O in Stage I can be expressed as: Fe3+ →Fe(3+δ)++δ e- and 4O2- →4O(1.5+0.25δ)- +(2-δ)e-. Stage II is a one-phase reaction in the second plateau, with pseudo-cubic Li3FeO4 converting into pseudo-cubic LiFeO2 (Li3FeO4→2Li++2e+O2+LiFeO2) and the releasing of one O2 from the Fe-O framework.  The valance evolution Fe and O in Stage II can be expressed as: Fe(3+δ)++ δ e- → Fe3+ and 4O(1.5+0.25δ)-→2O2-+O2+(2+δ)e-. Theoretical modeling confirms the formation of pseudo-cubic phase and O2 releasing in the second stage.  High energy barrier was found for conversion from the pseudo-cubic phase back to antiflorite phase with lithiation and the O2 absorption, explaining the irreversibility of the LFO.

Figure 1
Li2FeP2O7 Nanoparticles with Enhanced Electrochemical Performance Synthesized by a Sol-Gel Method
Authors: Zheng Junchao
Published: February 2020

There are intensive research activities for alternative electrode materials in the next generation of rechargeable lithium ion batteries, particularly for those used in hybrid and pure electric vehicles. Phosphate-based cathode materials have been a considerable investigation due to its attractive properties (low-cost, abundant iron and phosphate groups). Since the monoclinic structure of lithium iron pyrophosphate (Li2FeP2O7) was ﬁrst reported in 2010, it has captured the attention of researchers due to its higher reversible potential of 3.5 V vs. Li/Li. In this work, Li2FeP2O7 nanoparticles with 50-100nm in diameters were synthesized through a sol-gel method, the particles are coated by carbon layers (about 5 nm), they can deliver an initial discharge capacity of 112, 100 and 90.0 mAh g-1 at the rates of 0.025C, 0.1C and 1C, respectively. The capacity retention can still reach about 95.2% after 200 cycles at 1C.
Phosphorus Electrodes for Li and Na-Ion Batteries: Structural Analysis and Reaction Intermediates
Authors: Griffith Kent J. , Mayo Martin , Morris Andrew J. , Grey Clare P.
Published: February 2020

Phosphorus, in several allotropic variations, is emerging as a high capacity anode candidate for lithium and sodium batteries.  The theoretical capacity for Li3P/Na3P is 2596 mA·h·g-1, far exceeding carbon and on par with the best known lithium and sodium battery anodes.  To date, some composites of carbon with red phosphorus1,2, black phosphorus3–5, or phosphorene6–8have been investigated; however, the amorphous or poorly crystalline nature of these composites has hindered the understanding of phosphide intermediates and reaction mechanisms.  Additionally, the nature of the phosphorus–carbon composites is not fully understood.  A more complete chemical and structural picture is required to identify failure mechanisms and improve the lifetime of these promising electrodes.

Solid state nuclear magnetic resonance (NMR) offers unique insight into the complex chemistry of phosphorus composites and lithium phosphides.  Nucleus-specific local atomic structure information is obtained for amorphous red phosphorus and its mechanochemical conversion to black phosphorus, which is relevant to all studies of phosphorus electrodes.  Furthermore, the lithiation mechanism and lithium phosphide reaction intermediates are elucidated via 7Li and 31P NMR in combination with structure prediction from ab initio random structure searching and atomic species swapping methods.  While Li3P is a known reaction product – observed via x-ray diffraction – other stable or metastable lithium phosphide intermediates have been hypothesized but not conclusively determined.  We provide experimental and theoretical support for a range of amorphous and well-defined LixPy phases.

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Figure 1
Synthesis of Mono-Dispersed Olive-Shaped LiFePO4 Nanoparticles By Polyol Method
Authors: Shen Yue , Hai Chunxi , Zhou Yuan , Zeng Jinbo , Sun Yanxia
Published: February 2020

Since the use of olivine-structured lithium iron phosphate (LiFePO4, LFP) as a cathode material for rechargeable lithium batteries was first reported by Goodenough and co-workers in 1997, LFP has been extensively and intensively studied, owing to its significant advantages including high theoretical capacity (170 mAhg-1), long cycle life(≥2000), acceptable operating voltage (3.4V vs. Li+/Li), environmental benignity, high safety, and low cost. Unfortunately, LFP possesses a major drawback in its sluggish kinetics of electron and lithium-ion transport, which restricts its rate performance. To date, many studies have been made to reduce the particle size and incorporate carbon additives of LFP,  so as to improve the electronic conductivity and thus enhance the diffusion of Li ions across the LFP/FePO4 interface. Many techniques have been developed to synthesize nanosized LFP with uniform size distributions, which include the hydrothermal method, polyol and solvothermal methods, sol-gel  methods,  reverse  micelle  process and spray pyrolysis. Among them, the polyol method is considered one of the most facile and efficient methods to synthesize nanosize LFP with high crystallinity. Therefore, in this study, we would like to control the size, crystallization degree, morphology of LFP particles via a facile, low temperature polyol method to improve its ionic and electric transport properties. In this method, the polyol solvent (ethylene glycol) could generate a reductive atmosphere even in the absence of any reductive agent. Highly-dispersed LFP cathode nanospheres with olive-shape was synthesized by a simple polyol refluxing process without any post heat treatments. As-obtained samples were characterized by XRD, FE-SEM, TEM, BET etc. As confirmed by these characterization results that olive-like LFP nanoparticles with high crystallization degree were successfully prepared in this study. And the sizes of these nano/micro-particles are ranged from 50 nm to 800 nm. The various processing parameters, namely, reaction temperature and material ratio, have been varied, and the effects on the growth of LFP particles have been analyzed systematically to optimize the preparation condition. Finally, the electrochemical properties especially the rate performance of as-resulted LFP nanoparticles, employing the reported as comparison,  were discussed, which is the key point of their application in Li ion batteries.

Figure 1
Enhanced Electrochemical Properties of LiNi0.5Co0.2Mn0.3O2 Cathode Materials with RuO2 Coating Layer By Atomic Layer Deposition
Authors: Hong Tae Eun , Byeon Mi Rang , Jang Yujin , Jeong Euh Duck , Kim Soo-Hyun
Published: February 2020

Ni-based cathode materials have been as an alternative to LiCoO2[1,2]. Therefore, many studies have been performed to solve the inherent problems of Ni-base cathode materials [3].  However, reasonable solution for rate performance and thermal stability of Ni-based cathode materials has not been reported. Coating method on the cathode material may become the solution technique for electrochemical properties.

In this study, LiNi0.5Co0.2Mn0.3O2 cathode materials were prepared by co-precipitation method. RuO2 coating layer was deposited on LiNi0.5Co0.2Mn0.3O2powder using a shower head type PEALD reactor (Lucida-M100, NCD Technology), with IMBCH Ru [IMBCH = (η6-1-isopropyl-4-methylbenzene)(η4-cyclohexa-1,3-diene)] as a precursor.

We propose a new coating method for cathode materials using atomic layer deposition. The physical and electrochemical properties of RuO2 coated LiNi0.5Co0.2Mn0.3O2 cathode materials have been thoroughly investigated. Compared to various metal oxides, we will show that the optimization of RuO2 coating layer can be significantly improved the electrochemical performance of LiNi0.5Co0.2Mn0.3O2cathode materials.

References

[1] Y. S. Lee, D. Ahn, Y. H. Cho, T. E. Hong, J. Cho, J. Electrochem. Soc., 158 A1354 (2011)

[2] E. Rossen, C. D. W. Jones, and J. R. Dahn, Solid State Ionics, 57 311 (1992)

[3] Y. Kim, H. S. kim, S. W. Martin, Electrochim. Acta, 52 1316 (2006)
Carbon-Laminated Silicon/Graphene Composite Anodes with Improved Capacity and Cycling Stability
Authors: Chiu Kuo-Feng , Leu Hoang-Jyh , Su Shih-Hsuan , Yang Po-Chun
Published: February 2020

An unconventional route was adopted for fabricating Si/graphene composite anodes. Well crystallized silicon powders purified from the silicon waste mortar of solar cell fabrication were mixed with graphene suspended polyvinylidene fluoride (PVDF) solutions, and calcined directly on metal current collectors. It was found that PVDF was pyrolyzed to form a carbon scaffold which laminated the Si and graphene. The graphene sheets were able to hold the Si powers, preventing them from stress-cracking due to large volume change during charge and discharge processes. Silicon anodes using conventional coating method with PVDF binder and carbon black were also fabricated for comparison. The carbon laminated Si anodes (Si/C) exhibit an initial delithiation capacity of more than 2500 mAh/g at 0.1 C, which is greatly higher than the pristine Si anode (capacity of only 8 mAh/g at 0.1 C). By adding graphene in the composite, the carbon laminated Si/graphene anodes show improved cycling stability, with a 1 C delithiation capacity of 1420 mAh/g after 60 cycles, which is twice as high as Si/C anodes. The results indicate that high capacity and high cycling stability can be achieved by a pyrolysis based carbon lamination process in which graphene and Si powders are attached to each other.
Development of TiO2 Based Anodes with Ionic Speek Binder in Lithium Ion Battery
Authors: Leu Hoang-Jyh , Chiu Kuo-Feng , Su Shih-Hsuan , Liao Po-Yen
Published: February 2020

In this work, the commercial titanium dioxide (TiO2) powder was used for anode material in lithium ion battery, and the traditional PVDF binder was replaced by sulfonated poly(etheretherketone) (SPEEK). The SPEEK acts as additional Li-ion conductor on the TiO2 anode, which increases the active area and enhances electrochemical performance. The traditional binder PVDF and ionic binder, SPEEK, were compared in morphology, crystal structure, and electrochemical properties. The scanning electron microscope (SEM), field emission scanning electron Microscopy (FE-SEM) and X-ray diffraction (XRD) were used to characterize the morphology and crystal structure of the anodes with different binders. Afterwards, the TiO2 anodes were packed into half cells (coin cell 2032) to understand the electrochemical properties of this composite material by cyclic voltammetry, charge-discharge, and A/C Impedance. In the initial stage of this experiment, direct coatings of TiO2 anode did not show ideal electrochemical properties. However, after the heat treatments, the performances of electrochemical properties for TiO2 anodes has optimized by applying series of temperatures (No treatment, 200oC, 300oC, and 400oC) for heat treatments. It is proved that the ionic binder, SPEEK, can replace the traditional PVDF binder. The result has shown that ionic-binder, SPEEK, can enhance the cycle life as well as the high rate performance of the TiO2 anodes. The A/C impedance test has confirms that the enhancement of electrochemical of properties is due to the reduction of charge transfer resistance by the ionic conducting SPEEK binders.
All-Solid-State Flexible Lithium Batteries on Polyimide Substrate Using Excixmer Laser Annealing
Authors: Yim Haena , Sung Yung-Eun , Choi Ji-Won
Published: February 2020

As the demands of wearable electronics increase, the development of flexible power sources has become very important to satisfy them. All-solid-state lithium batteries have attracted huge attention over the recent years due to their safe characteristic and wide electrochemical stable window compared to those of liquid electrolyte-based lithium rechargeable batteries, which allows high operating voltage without any worries on safety problems at bending state.However, the cathode thin film, which is a critical component of thin film battery, certainly needs to be crystallized at high temperature because of the hindrance of solid-state lithium diffusion from any imperfections in the crystal. Eventually, the polymer substrate goes through sudden changes because of its poor resistance to high temperature, so a new direction of crystallization should be considered. 

In this work, we present a new fabricating method for all-solid-state flexible lithium batteries using excimer laser annealed cathode thin films, which facilitates fast crystallization of active materials with no damage on substrate. The excimer laser annealed cathode thin films were crystallized without a damage of polyimide substrate. Structural properties of the thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The electrochemical properties were carried out using WBC3000 battery cycler. The initial capacity of developed flexible battery on polyimide substrate was 20 μAh μm-1 cm-2 at 0.2 C-rate. It was confirmed that red light-emmitting diode light was turned on continuously during the bending state. We expect that this approach for fabricating flexible batteries will be practically applied for micro-powered flexible electronic devices.
Evaluation of the Electrochemical Performance of Li4Ti5-XAlxO12 as Anode Material for Lithium-Ion Batteries
Authors: Ncube Ntombizodwa M , Zheng Haitao
Published: February 2020

Rechargeable lithium-ion batteries (RLIBs) have shown potential as future batteries for electric vehicles and portable electronics. This results from their high energy density, high power, environmental safety, low cost electrode materials and long life. While during the charge/discharge processes the lithium-ions intercalate and de-intercalate from the electrodes, such that the performance of the RLIBs depends mostly on the material properties. This perspective has led to the development of novel anode materials to advance from the use of graphite and other carbon based materials. Some drawbacks of these materials include safety concerns, low operating voltage, and shorter lifetime. The spinel-type lithium titanate (Li4Ti5O12, LTO) as a promising anode material has become more attractive for its negligible lattice changes during cycling, high theoretical capacity (175 mAh/g), flat voltage plateau of 1.55 V vs Li/Li+, long cycling stability and environmental compatibility. This outlook introduced more studies on the improvement of the low electronic conductivity and low diffusion coefficient of the Li-ions in LTO which hinders the advancement of the LTO to meet requirements for high capacity large scale applications. In this work, a comprehensive study of doping with aluminium (Al) on the titanium site was carried out with aim to improve the capacity and cyclability performance. Al-doped LTO in the form of Li4Ti5-xAlxO12 (x = 0, 0.05, 0.1, 0.15, 0.2) was synthesized via a conventional solid state reaction in an air atmosphere. Al-doping does not change the plateau voltage (1-2.5 V) of LTO during cycling, but showed a slight increase in the polarization of the electrode especially for 0.05Al. Li4Ti4.85Al0.15O12 demonstrated an increase in the initial discharge capacity (172 mAh/g) relative to Li4Ti5O12 (154 mAh/g) and an improved rate capability and cyclability. The enhanced electronic conductivity and rate capability can be attributed to the mixture of the redox couple of Ti3+/Ti4+ and high Li+ diffusivity. Moreover, the enhanced cyclability results from the stability of Al-O than for Ti-O in the octahedral coordination polyhedron, thus strengthening the stability of the spinel structure.
Towards an All Solid State Lithium Battery Beyond 5 V
Authors: Windmüller Anna , Tsai Chih Long , Gehrke Hans Gregor , Uhlenbruck Sven , Guillon Olivier
Published: February 2020

Spinel cathodes for Lithium Ion Batteries (LIB), such as LiCoMnO4, offer higher operational voltages and higher energy densities than common LIB cathodes, like LiCoO2 [1]. Compared to LiCoO2 the energy density of a LiCoMnO4 cathode is increased by 25%. Therefore, high voltage LIBs based on spinel cathodes are considered as possible candidates for future lithium battery technologies. However, commonly used liquid electrolytes are unstable at potentials above 4.5 V , which is the minimum operational voltage for spinel cathodes [2,3]. To access the full energy density of LiCoMnO4 cathodes (~5.3 V) an all solid state approach is chosen by replacing the liquid electrolyte by a solid state electrolyte ceramic [4]. The processing of a cathode for an all solid state battery comes along with new requirements to the cathode material. Compared to common particulate based cathodes a different functional structure has to be developed to assure electronic and ionic diffusion paths. Additionally, it has to be compatible to the given solid electrolyte and – depending on the processing techniques – withstand higher temperatures during manufacturing. Lithium-manganese spinels in particular are known to be unstable at higher temperatures and tend to release lithium and oxygen from their lattice [5,6]. Therefore, sintering and stability studies for LiCoMnO4 were carried out to find a processing route that leads to a high relative density without decomposition of the material. Additionally, different conceptual cathodes were tested and characterized structurally, microstructurally and regarding their electrical properties. The completion of this study finally leads to a cathode supported all solid state battery with lithium phosphorous oxy-nitride as solid electrolyte processed by physical vapour deposition.

References

[1]  Whittingham MS. Chem. Rev. 2004;104:4271–302.

[2]  Goodenough JB, Kim Y. Chem. Mater. 2010;22:587–603.

[3]  Xu W, Chen X, Ding F, Xiao J, Wang D, Pan A, Zheng J et al. Journal of Power Sources 2012;213:304–16.

[4]  Li J, Ma C, Chi M, Liang C, Dudney NJ. Adv. Energy Mater. 2015;5:n/a-n/a.

[5]  Pasero D, Souza S de, Reeves N, West AR. J. Mater. Chem. 2005;15:4435–40.

[6]        Thackeray MM, Mansuetto MF, Dees DW, Vissers DR. Materials Research Bulletin 1996;31:133–40.
The Effect of Carbon Starting Material on Li/CFx Batteries with Graphene Paper As Flexible Current Collector
Authors: Yang Weijing , Dai Yang , Zhang Maohui , Dang Guoju , Min Fanqi , Xie Jingying
Published: February 2020

Li/CFx batteries are known to have the highest theoretical specific capacity in comparison to other primary lithium batteries, which are commonly used for many applications such as emergency power source, cameras, memory back-up, electronic counter, electrical lock, electronic measurement equipment, military and implantable medical devices. However, the low electrical conductivity of CFx limits the development of Li/CFx batteries where high power density is needed. Graphene paper has been developed as flexible current collector to improve the power density of Li/CFx batteries. As known the importance of carbon starting materials, recently, three different types of carbon(coke, mesoporous carbon and graphite) have been fluorinated and developed, in order to promote some particular electrochemical parameters, namely the power density, the discharge potential, or the energy density. 

Overall, the carbon fluorides with graphite as precursors present no voltage delay at the beginning of discharge and excellent electrochemical properties at high current density. The carbon fluorides with mesoporous carbon as precursors own the highest discharge potential. While, carbon fluorides with coke as precursors deliver the highest energy density(810 mAh/g). As the result shown, carbon starting materials strongly influence the electrochemical performances of Li/CFx batteries. It is necessary and significant to choose precursors and design the battery system according to varied applications.

The main part of this work was supported by National Nature Science Foundation of China (No.21373137) and Shanghai Municipal Science and Technology Commission (No.15DZ2282000 and No.14JC1491800).

Figure 1
A New Partial Atomic Layer Deposition Coating Technique to Assess Battery Cycle-Performance Effects of Different Surface Sites of LiNi0.5Mn0.3Co0.2O2
Authors: Jackson David H. K. , Chang Wansoo , Morgan Dane , Mahanthappa Mahesh K. , Kuech Thomas F.
Published: February 2020

In order to better understand electrolyte degradation at cathode-electrolyte interfaces and mechanisms by which coatings can protect against such degradation, it is important to determine to what extent capacity fade occurs predominantly at highly reactive sites vs. uniformly over the cathode surface. To explore this question we have developed an atomic layer deposition (ALD) based thin film coating technique to study the varied effects of LiNi0.5Mn0.3Co0.2O2 (NMC) surface sites on Li-ion battery charge capacity fade. Small organic molecules selected for their chemical functionality are grafted to the oxide surface to block ALD coating of NMC surface sites of complimentary chemical reactivity to the template molecules. The ALD films are deposited using the well-established Al2O3 process, which has been studied extensively in the coating of NMC and similar cathode materials. After ALD, the organic template molecules are removed using ozone treatment, leaving the underlying reactive surface sites of NMC exposed. By exposing different surface sites, it is possible to study their separate effects on battery cycle performance. The protocol for partial ALD coating is established, with screening performed on some candidate template molecules. Both the reproducibility of the grafting, the partial ALD coating, and the template removal are established. The benzylbromide (BB) template molecule will react with hydroxyl groups at the surface, while benzoic acid (BA) will react with basic metal oxide sides. In order to insure the stability of the grafted template molecules, deposition was performed at 100°C, a temperature lower than that employed in a typical ALD process. X-ray photoelectron spectroscopy shows that the BA-NMC surfaces have a higher proportion of Ni exposed on the surface compared to a control sample, while the BB-NMC surface does not have any disproportionate elemental composition. Preliminary results show that despite similar amounts of film deposited, the BA-NMC surface performs better than BB NMC in terms of discharge capacity fade during cycle-performance testing. This preliminary result implies that Ni sites on the NMC surface do not negatively affect cycle-performance. This result is contrary to other recent reports in the field reporting a connection between NiO and solid electrolyte interphase formation, showing further insight into the complex electrochemical phenomena occurring at the cathode surface.
Mapping of Spatial Inhomogeneities with Laboratory X-Ray Diffraction
Authors: Wolf Mark , Khawaja Sara , Cabana Jordi
Published: February 2020

We have developed a new laboratory X-ray diffraction technique to probe

meso-scale inhomogeneities in battery cathode materials. Conventional

diffraction uses an X-ray beam that covers most of the cathode

surface, giving average properties over all locations. In contrast,

our technique uses a laboratory diffractometer with a sub-millimeter

beam to extract location-specific structure information. Up until now,

this has only been reported with synchrotron radiation. We have used

this technique to uncover inhomgeneities related to a variety of

factors, such as preparation technique, the size and position of the

anode, and the charge rate of the cell. For example, in one

experiment, sections of an LiMn₂O₄ cathode were found to lag behind

the global state in areas of poor contact with the current

collector. This effect was not seen at slow rates (C/10), however,

suggesting that alternate electrical pathways are still available,

though kinetically less viable. This technique can also be used to map

an electrode's cross-section to find effects occuring along the

direction of charge flow.
Cycling and Aging Studies of Li-Based Cathode Materials Via Aberration-Corrected STEM
Authors: Phillips Patrick J , Abraham Daniel P , Klie Robert F
Published: February 2020

The role of aberration-corrected scanning transmission electron microscopy (STEM) in materials characterization is examined with respect to layered-oxide cathode materials for battery applications. STEM-based methods are quickly becoming the most promising characterization tools for these materials, owed largely to the wide-range of techniques available on advanced STEM instruments, including the direct imaging of both heavy and light elements, and both energy-dispersive X-ray (EDX) and electron energy loss (EEL) spectroscopies. The current talk will focus on multiple Li-based, Mn-containing oxide cathode materials, for example, Li2MnO3 and Li(Ni0.5Co0.2Mn0.3)O2), characterized via STEM methods, in pristine, cycled, and in-situ irradiated states. The latter allows for single particle tracking of the dynamic processes occuring upon Li and O loss from the material, and is a form of accelerated ageing compared to the structural and electronic changes which occur upon electrochemical cycling. Various imaging modes, including high/low angle annular dark field (H/LAADF) and annular bright field (ABF), in conjunction with EELS/EDX, will be used extensively for this analysis, while parameters such as Mn valence, O presence, and light element occupation and intercalation will be discussed.
In-Situ X-Ray Studies of Unmodified Commercial Pouch Cells
Authors: Bond Toby M , Zhou Jigang , Reid Joel
Published: February 2020

Synchrotron techniques, including synchrotron X-ray diffraction (SR-XRD) and X-ray absorption spectroscopy (XAS), have been widely used over the past twenty years to investigate the chemical and physical behavior of batteries.  The uniquely high brilliance and coherence of synchrotron light has made it especially well-suited for in-situ analysis of batteries, as data can be acquired very quickly with excellent spectral and spatial resolution
[1]
.

Generally in-situ studies of batteries employ a custom-made research cell that is designed with “windows” in the casing that are x-ray transparent.  Such cells typically employ a simple coin-cell-type design where two discs of electrode material are pressed together in an air-tight assembly
[2, 3]
.  While these types of cells are very useful and convenient for most materials research, they cannot exactly replicate the conditions present in many common commercial cells, and they are not generally suitable for long-term studies on ageing and degradation.

The work presented here demonstrates several examples of how synchrotron techniques can be used to analyze unmodified commercial pouch cells.  With high brilliance and tunability of incident wavelength, synchrotron light can be used to penetrate commercial cell casings and analyze active electrode material in-operando.  At the Canadian Light Source, SR-XRD was used to analyze the crystal structure and phase changes in an operating commercial nickel-manganese-cobalt-oxide/graphite pouch cell.  Transmission SR-XRD was also used to map structural inhomogeneities in cell components with high spatial resolution.  In-operando XAS was also successfully carried out on an unmodified commercial pouch cell, which will provide a simple means of monitoring changes in structure and redox chemistry as commercial batteries undergo long-term ageing, cycling, and stress testing.

[1] Yoon W-S, Grey CP, Balasubramanian M, Yang X-Q, Fischer DA, McBreen J.  Electrochem Solid-State Lett., 2014, 13, 1051-1061.

[2] De Marco R, Veder JP.  Trends in Analytical Chem., 2010, 29, 6.

[3] Herklotz M, Scheiba F, Hinterstein M, Nikolowski K, Knapp M, Dippel AC, Giebeler L, Eckert J, Ehrenberg H.  J. Appl. Cryst., 2013, 46, 1117-1127.
One-Pot Synthesis of Iron Oxide Nanoblock Deposited on 3D Porous Graphene Architecture for Lithium Ion Storage
Authors: Yun Sol , Park Ho Seok
Published: February 2020

The hierarchical architecturing and hybridization of iron oxide is very important for achieving multifunctional capability that makes it possible for practical applications. In particular, hierarchical architecturing of graphene/iron oxide hybrids in a three-dimensionally (3D) manner is expected to become an innovative chemical approach for full potential of respective functionality. In addition to intrinsic material properties, such a hierarchical structure constructed by graphene nanosheets and iron nanoparticles takes advantages of 3D interconnected macroscopic structure in terms of a large accessible area, fast mass and ion transport, percolated charge transfer, and structural integrity.

In this study, hierarchically structured reduced graphene oxide (hrGO)/α-Fe2O3 nanoblock hybrids (hrGO/α-Fe) are synthesized via a one-pot, hydrothermal self-assembly process. All in one synthetic approach is very simple yet useful for simultaneously constructing 3D macroscopic rGO structures and growing α-Fe2O3 NBs. The 3D macroporous structure of hrGO/α-Fe NBhs is constructed, while α-Fe2O3 nanoblocks (NBs) in a proximate contact with the hrGO surface are simultaneously nucleated and grown during a hydrothermal treatment. The discrete α- Fe2O3 NBs are uniformly distributed on the surface of the hrGO/α-Fe and confined in the 3D architecture, thereby inhibiting the restacking of rGO layers and maximizing their functionalities.

In order to demonstrate the superiority of the hrGO/α-Fe NBhs, we applied them into lithium ion battery anodes. The specific capacity of the commercial rGO/α-Fe dramatically decreased from 662.6 mAh/g at 50 mA/g to 83.6 mAh/g at 1000 mA/g with the capacity retention of 12.6%. In a sharp contrast to the commercial rGO/α-Fe, the hrGO/α-Fe NBhs exhibited better rate performance from 497.7 mAh/g to 210.3 mAh/g with the capacity retention of 42.3%. After 60 cycles at 100 mA/g, the commercial rGO/α-Fe showed highest initial discharge capacity of 566.5 mAh/g, but it was further decreased to 380.8 mAh/g (67.2%) of initial capacity. By contrast, the hrGO/α-Fe NBhs showed no capacity fading, maintaining initial capacity of 472.8 mAh/g. Despite lower coulombic efficienty and initial capacity, the hrGO/α-Fe NBhs show better rate and cyclic performances than those of commercial rGO/α-Fe due to the uniform distribution of discrete α-Fe2O3 NBs and electronic conductivity, macroporosity, and buffering effect of the hrGO for an application into lithium ion battery anode.
Improved Cyclability of Silicon/Porous-Carbon Composite with Ag Nanoparticles for Lithium-Ion Battery Anodes
Authors: Lee Sun-Young , Chung Eun Hyuk , Hong Tae Eun , Bae Jong-Seong , Lee Jung Kyoo , Kim Jeom-Soo , Jeong Euh Duck
Published: February 2020

A Silicon/Porous-Carbon (Si/Porous-C) composite with Ag nanoparticles was prepared by the co-assembly of polyvinylidene fluoride (PVdF), nano-SiO2 (~20 nm), AgNO3 and Si nanoparticles (~ 50 nm) followed by a carbonizing process and subsequent removal of SiO2 template. The Si/Porous-C and Ag/Si/Porous-C composite were characterized by scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD). Ag nanoparticles remained even after heat treatment at high temperature and hydrofluoric acid etching. The Ag/Si/Porous-C composite electrode exhibited good electrochemical performances with a reversible capacity of 1,470 mAh/g as an anode material in lithium-ion cells, showing a stable capacity of 1,150 mAh/g after 100 cycles at a rate of 500 mA/g per hour. Cycling performances of the Si/Porous-C and Ag/Si/Porous-C composite electrodes were determined at various rates as shown in figure. The Ag/Si/Porous-C composite electrode showed better rate capability and recovery as the rates decreased, while the capacity of the Si/Porous-C composite electrode faded drastically as the rates increased.

Figure 1
Synthesis and Electrochemical Characterization of New Electro-Active Polymer Bearing TEMPO Functional Groups
Authors: Sadki Mohand said
Published: February 2020

Synthesis and electrochemical characterization of new electro-active polymer bearing TEMPO functional groups

L.Assumaa, A.Santiagoa, Y. Kervallaa, JM. Mouescaa, V. Maurela, T. Gutelb, L. Duboisa, S. Sadkia

a. INAC-SPrAM-SYMMES, bLITEN-DEHT-Laboratoire des Composants pour Batteries, CEA 17, rue des Martyrs, Grenoble

Organic radical species, particularly pendant nitroxide radical polymers, have been explored as a cathode-active, charge-storage material for secondary Li-ion batteries1. However, nitroxide radical contained polymers are derivatives of conventional plastics, which are insulator, and a very large amount of conducting agents (such as carbon black, graphite, graphene and carbon fibers), even up to 60-80 wt% of the total electrode, is required in the fabrication of the composite electrode and this leads to a decrease of the composite electrode capacity2. In order to decrease de quantity of conducting agents we combined a stable nitroxide radical with a conductive polymer backbone constituted by 2,7-bisthiophene carbazole, which is characterized by high thermal stability and high conductivity. In this work we present the synthesis of this new electro-active conductive redox polymer, the electrochemical characterization, the ESR characterization and battery test. The previous results showed a very high electrochemical reversibility of this system, and a superposition between the redox potential of bisthiophene carbazole backbone and nitroxide radical . Moreover, the preliminary battery test displayed a good capacity (about 60 mAh / g) and a good life cycle, about 50 cycles for a discharge rate equals to C/10.. Thanks to these preliminary results, this polymer could be a viable alternative to the actual radical redox polymers.

(1) Song, Z.; Hapshen Z., Energy and environmental Science
2013
, 60, 2280.

(2) Lihuan X., Fang, Y., Chang, S., Lvlv Ji, Cheng Z., Electrochimica Acta, 2014,
130,148-155.
Nanowire Devices for Electrochemical Energy Storage
Authors: Mai Liqiang
Published: February 2020

One-dimensional nanomaterials can offer large surface area, facile strain relaxation upon cycling and efficient electron transport pathway to achieve high electrochemical performance. Hence, nanowires have attracted increasing interest in energy related fields. We designed the single nanowire electrochemical device for in situ probing the direct relationship between electrical transport, structure, and electrochemical properties of the single nanowire electrode to understand intrinsic reason of capacity fading. The results show that during the electrochemical reaction, conductivity of the nanowire electrode decreased, which limits the cycle life of the devices.1 Then, the prelithiation and Langmuir-Blodgett technique have been used to improve cycling properties of nanowire electrode. Recently, we have fabricated hierarchical MnMoO4/CoMoO4 heterostructured nanowires by combining "oriented attachment" and "self-assembly".2 The asymmetric supercapacitors based on the hierarchical heterostructured nanowires show a high specific capacitance and good reversibility with a cycling efficiency of 98% after 1,000 cycles. Furthermore, we fabricated Li-air battery based on hierarchical mesoporous LSCO nanowires and nonaqueous electrolytes, which exhibits ultrahigh capacity over 11000 mAh g-1.3 We also designed the general synthesis of complex nanotubes by gradient electrospinning, including Li3V2(PO4)3, Na0.7Fe0.7Mn0.3O2 and Co3O4 mesoporous nanotubes, which exhibit ultrastable electrochemical performance when used in lithium-ion batteries, sodium-ion batteries and supercapacitors, respectively.4 In addition, we fabricated all-solid-state 3D on-chip micropseudocapacitors with ultrahigh energy and power densities.5 Our work presented here can inspire new thought in constructing novel one-dimensional structures and accelerate the development of energy storage applications.

Reference

[1] L. Q. Mai, Y. J. Dong, L. Xu, C. H. Han. Nano Lett. 2010, 10, 4273;

[2] L. Q. Mai, F. Yang, Y. L. Zhao, X. Xu, L. Xu, Y. Z. Lou. Nature Commun. 2011, 2, 381;

[3] Y. L. Zhao, L. Xu, L. Q. Mai, C. H. Han, Q. Y. An, X. Xu, X. Liu, Q. J. Zhang. PNAS. 2012, 109, 19569;

[4] C. J. Niu, J. S. Meng, X. P. Wang, C. H. Han, M. Y. Yan, K. N. Zhao, X. M. Xu, W. H. Ren, Y. L. Zhao, L. Xu, Q. J. Zhang, D. Y. Zhao, L. Q. Mai. Nature Commun. 2015, 6, 7402;

[5] X. C. Tian, M. Z. Shi, X. Xu, M. Y. Yan, L. Xu, A. Minhas-Khan, C. H. Han, L. He, L. Q. Mai. Adv. Mater. 2015, 27, 7476.
Add Oxygen Additions to Prolong Cyclelife of Hydride Batteries
Authors: Shen Yang , Noréus Dag
Published: February 2020

At first the title might sound counter intuitive, but metal alloy corrosion during cycling influences the cycle life of NiMH batteries in two detrimental ways. Firstly, it consumes the electrolyte drying out the battery resulting in increasing internal resistivity. Secondly, the corrosion produces hydrogen and when the hydrogen is absorbed in the MH electrode, it shifts the electrode balancing. This rapidly consumes the overcharge reserve in the battery leading to increased internal oxygen pressures in the end of the charging cycle, which in turn makes the battery to vent through the safety valve, accelerating the drying out of electrolyte. This is aggravated by the shift of the Ni-electrode balance to higher pressures in the PCT curve, as this contaminates the oxygen with hydrogen. The recombination of oxygen is significantly slowed down by the presence of gaseous hydrogen.1If oxygen could be added externally, it would react with the hydrogen in the metal hydride forming water. This will counter act the drying out by adding water to the electrolyte and at the same time as it restores the electrochemical electrode balance leading to reduced internal pressures when cycling the battery. This was tested in a bipolar NiMH module comprising 10 cells in series supplied by Nilar AB in Sweden. (cf. figure below) A special feature of the design is that it has a common gas space facilitating external addition of gases. By adding an oxygen aliquot every hundreds of cycles, we could eliminate the pressure build up as the battery aged and significantly reduce the increase in internal resistivity over long time cycling.

1) Z. Ye and D. Noréus, J. Power Sources 208, (2012) 232.

Figure 1
Compatibility Issues Between Electrodes and Electrolytes in Solid-State Batteries
Authors: Tian Yaosen , Shi Tan , Richards William Davidson , Bo Shou-Hang , Kim Jae Chul , Li Juchuan , Ceder Gerbrand
Published: February 2020

Solid-state batteries have recently attracted significant attention because of their advantages compared with conventional batteries employing liquid electrolytes. Remarkable success has been achieved in the discovery of ceramic alkali superionic conductors as electrolytes in solid-state batteries; however, obtaining a stable interface between these electrolytes and electrodes is difficult. Only limited studies on the compatibility between electrodes and solid electrolytes have been reported, partially because of the need for expensive instrumentation and special cell designs. Without simple yet powerful tools, these compatibility issues cannot be systematically investigated, thus hindering the generalization of design rules for the integration of solid-state battery components.

In this work, we present a methodology that combines density functional theory (DFT) calculations and simple experimental techniques such as X-ray diffraction(XRD), simultaneous differential scanning calorimetry and thermal gravimetric analysis (SDT), and electrochemistry to efficiently screen the compatibility of numerous electrode/electrolyte pairs. Employing a Na solid-state system as an example, we demonstrate the efficiency of our method by finding the most stable system (NaCrO2|Na3PS4|Na-Sn) within a selected chemical space (more than 20 different combinations of electrodes and electrolytes). Important selection criteria for the cathode, electrolyte, and anode in solid-state batteries are also derived from this study.

This work has two important implications for the future studies in the related fields: (1) the study of the stability window of the electrolyte and the reaction conditions and products of the reactions between electrode and electrolyte provide an essential guide for integrating all-solid-state battery components; and (2) this current method can significantly accelerate the expansion of the electrolyte/electrode compatibility database.

Figure 1