bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Cycling Stability of Conversion and Alloying Anodes through the Use of Nanomaterials
Authors: Rehnlund David , Lindgren Fredrik , Böhme Solveig , Nordh Tim , Zou Yiming , Pettersson Jean , Bexell Ulf , Edström Kristina , Nyholm Leif 
Published: February 2020

In order to meet the growing need for portable energy storage future batteries need to provide improved energy densities. One major problem lies in the current use of intercalation based electrode materials which are typically limited to storing one lithium ion per formula unit. Improved energy storage can be achieved through the use of conversion and alloying reactions where it is possible to store multiple lithium ions per formula unit. Even though impressive energy densities can be obtained through the use of conversion and alloying anode materials, only surpassed by the use of lithium metal itself, these systems are typically plagued by capacity fading during cycling. The origin is generally ascribed to irreversible reactions with the electrolyte amplified by major volume expansion, causing the growth of a solid electrolyte interphase (i.e. SEI). One promising strategy to address this issue is through the use of nanosized electrode materials (e.g. Si nanoparticles), as it has been shown that nanoparticles and nanowires show better cycling stability than their bulk counterparts [1, 2]. Large particles (i.e micrometer sized) form cracks during cycling as opposed to smaller particles (i.e. < 150 nm) [3]. Even though the use of nanoparticles can reduce crack formation and the accompanied SEI growth, capacity fading is still observed for these systems. Our work has focused on studying freestanding nanostructured conversion materials (e.g. Cu2O nanowires), which offer in depth analyses of the conversion reactions without disturbance from binders or conducting additives. Contrary to previous understanding nanosized Cu2O thin films and multi-layered nanostructures show an increase in capacity during cycling [4, 5]. This behaviour is caused by improved access to the entire material when using the nanomaterials. The system has also shown improved performance during cycling likely caused by electrochemical milling of the particles thereby consistently reducing the particle size and thus allowing more of the material to be accessible. With the successful use of nanosized conversion materials our research is now focused on addressing the stability problems of alloying materials by studying the effect of nanomaterials.
References:
1. A. Magasinski, et al.. Nat. Mater., 2010. 22: p. 353-358
2. C.K. Chan, et al.. Nat. Nanotechnol., 2008. 3: p. 31-35
3. X. H. Liu, et al.. Adv. En. Mater., 2012. 2: p. 722-741
4. M Valvo, et al.. J. Mat. Chem. A., 2014. 2: p. 9574-9586
5. D. Rehnlund, et al.. Nanoscale, 2015. 7: p. 13591-13604

Figure 1
Improved Electrochemical Performance in Advanced Lithium-Ion Batteries with Porocarb® As Functional Additive
Authors: Rohde Michael , Büttner Niklas , Kuhn Andreas , Moerseburg Erik , Weingarth Daniel , Becker Joerg , Pihan Sascha , Michaud-Bernlochner Julie , Samuelis Dominik , Hucke Thomas 
Published: February 2020

Electric vehicles face significant battery related challenges such as driving range, recharge time, durability, and cycle life. New concepts for improved and advanced battery technologies are required in order to increase driving range and durability, while simultaneously decreasing recharging time, weight, and cost. In recent years, new cell designs have been developed specifically for large scale applications in the automotive and stationary storage sectors.
A new electrode concept is to supplement with Heraeus Porocarb® porous particles as a functional additive to assure optimal mass transport of lithium ions by locally enhancing the effective diffusivity in the volume of the calendared electrode. Thereby achieving higher energy densities with improved cycle life and durability. Heraeus Porocarb is an electrochemically inert carbon with low specific surface with a unique porosity profile with distinct pore size regime. Its fully interconnected macropores allow for rapid ion transport, while the mesopores locally store electrolyte promoting mass transport and the pulse response of the cell.
Heraeus Porocarb can be implemented into lithium-ion battery electrodes in two different ways. More conventionally, a percolation-type approach can be taken for Porocarb particles which are smaller than the active material particles. Due to the interconnected and surface-accessible pore network in Porocarb, ionic percolation sets in at the same time as electronic transport, and local improvement of the porosity evolves into a globally interconnected transport pathway of Li+ions with low tortuosity.
The second electrode concept is an imprinting-type approach where the Porocarb particles used are larger and the active material is not only slightly imprinted but to a certain degree embedded in the Porocarb after calendaring. Due to the large contact area, very low resistances can be achieved in between the carbon and the active material, which alleviates contact resistance degradation and delamination, thereby extending cycle lifetime of the electrode.
The properties of Heraeus Porocarb will be presented with electrochemical data showing the enhanced performance and the so-called “Porocarb effect.”
This effect can be seen in lithium ion full cells by adding Porocarb in small quantities to the cathode. Therefore a representative cathode recipe were used, with an active material (NMC-111) content of 93 wt.%, 3 wt.% PVDF binder, 2.5 wt.% carbon black and 1.5 wt.% Porocarb. Reference cells were using a graphite instead of Porocarb. Two different cathode loadings were chosen: 120 g/m2 and 240 g/m2representing high-power and high-energy cell designs, respectively. The unique porous structure of Porocarb increases significantly the kinetics in the electrode and overcomes easily the drawbacks of the low rate capability of high energy cell.

Figure 1
Thin Films of Organic Electrode Materials for All-Solid-State 3D-Microbattery Applications
Authors: Nisula Mikko , Karppinen Maarit 
Published: February 2020

The miniaturization of electronic devices demands for energy storage systems of equal size. As the conventional liquid electrolyte cells do not scale well enough, the current focus is on all-solid-state thin film batteries. In order to increase the energy density while preserving the power density of the cells, nanostructuring of the substrate to increase the effective surface area is seen as a viable option. Such an approach places an apparent need for a thin-film deposition method capable of manufacturing the electrode and electrolyte materials on high aspect ratio substrates. A strong candidate for the task is the atomic layer deposition (ALD) technique which is based on sequential surface reactions of gaseous precursors. The surface saturation limited growth results in excellent conformality over complex surface features. However, the availability of ALD processes for Li-ion battery materials is severely lacking.
By utilizing combined atomic/molecular layer deposition (ALD/MLD) technique, we broaden the range of available electrode materials to those based on conjugated carbonyl systems. These organic electrode materials combine the high gravimetric energy density with abundant and environmentally benign constituents. We present demonstrative ALD/MLD processes for both anode and cathode materials and verify the electrochemical activity of the as-deposited thin films. Also shown is that the nanoscaling of the materials can be utilized to overcome the inherently poor kinetics of organic electrode materials without relying on any conductive additives. As the ALD/MLD method allows for making the cathode material directly in the fully-lithiated reduced state, the as-deposited pair can be combined into a full cell without an additional lithiation step.
Carbon Nanotube@MnO2 Hybrid Catalysts for Li-O2 Batteries
Authors: Wang Fan , Wen Zhaoyin , Shen Chen , Wu Xiangwei 
Published: February 2020

Rechargeable lithium-oxygen (Li-O2) battery has attracted enormous research attention due to its remarkably high theoretical energy capacity. However, the sluggish oxygen reduction and oxygen evolution reaction (ORR and OER) kinetics cause the high over potential, poor electrolyte stability and short cycling life.[1] Thus, the development of eﬃcient catalysts are required to effectively improve the Li-O2 battery performance.
The materials based on MnO2 are recognized as low-cost and eﬃcient catalysts for Li-O2 battery cathodes.[2] Here, in-situ growth of branched MnO2 nanosheets on multi-walled carbon nanotubes (MWCNTs) were generated through a one-pot reaction process and applied as cathode catalyst in a rechargeable Li-O2 battery. The MnO2 with the morphology of curved petal-like walls (about 50 nm in thickness) were homogeneously coated outside the CNT (about 40 nm in diameter) to form a core–shell nanowires.[3] The CNT@MnO2 hybrid showed excellent catalytic activity for both ORR and OER processes in Li-O2 batteries. Owing to its ultra-high specific surface area, it delivered a high reversible capacity of 1500 mAh·g-1 based on the mass of the hybrid. This core-shell structure can effectively prevent direct contact between the CNT and the discharge product Li2O2, thus avoiding or reducing the decomposition of CNT and the formation of Li2CO3 during charge process, which can also improve the conductivity of the cathode and increase the cycling performance of Li-O2 batteries. As a promising cathode catalyst in Li-O2 batteries, the branched CNT@MnO2 nanocomposite cathode exhibits a stable full discharge and charge cycling performance. As shown in figure 1b, about 250 cycles were achieved with a fixed capacity of 500 mAh·g-1 at a current of 100 mA·g-1.
The results shown that such a design of a core-shell architecture with a high conductive carbon nanotube in the center and MnO2 nanosheets uniformly coated on its surface both achieved the high conductivity and excellent catalytic activity in Li-O2 batteries.

Figure 1. Schematic illustrations of the transfer of electrons in CNT@MnO2 cathode (a). discharging and charging profiles (b) and cycle performance of Li-O2 battery with CNT@MnO2 cathode(c).

References:

[1] K. M. Abraham and Z. Jiang, J. Electrochem. Soc., 1996, 143 ,1 – 5.
[2] A. Debart, A. J. Paterson, J. Bao and P. G. Bruce, Angew. Chem. Int. Edit., 2008, 47, 4521-4524.
[3] Y. Chen, Y. Zhang, D. Geng, R. Li, H. Hong, J. Chen and X. Sun, Carbon, 2011, 49, 4434-4442.

Figure 1
Nickel-Rich Cathode Precursor Synthesis By Taylor Vortex Reactor
Authors: Kahvecioglu Feridun Ozgenur , Shin Youngho , Krumdick Gregory 
Published: February 2020

Progresses in lithium ion battery (LIB) materials are increasing by the development of new synthesis methods where the production of materials in a scalable and continuous route is very critical when the process development transfers to large scale quantities. In a LIB, one of the most performance limiting components is the cathode, which also limits the overall performance of the battery. Among the other synthesis methods, co-precipitation from aqueous processes is known to yield the best cation mixing within the structure, in particular for the synthesis of cathode precursors for batteries. Continuous stirred tank reactor (CSTR) is by far the most widely used systems utilized in battery industry, yet have low reproducibility, product efficiency, and undergo from very long stabilization times due to low mass transfer rate.
Here, we report a new emerging technology, Taylor Vortex Reactor (TVR), for the cathode precursor synthesis which overcomes many complexities encountered in CSTRs. As current research in the field is trending towards exploring nickel-rich compositions, we produced Ni0.6Mn0.2Co0.2 (OH)2 precursors employing a continuous hydroxide route in a TVR which were then lithiated to form active cathode particles. The effect of rotation speed on the morphology, and particle size and distribution of the precursors were investigated and reported. In general, higher rotation speed favored spherical particle formation with a smooth surface morphology along with a narrow particle size distribution. Tap densities of 1.77 – 1.98 g/cc for the precursor and 2.02 – 2.24 g/cc for the active materials were achieved, delivering 173 – 186 mAh/g discharge capacities at the first cycle with a C-rate of 0.1C when cycled between 4.3 - 3.0V.
Electrochemical Stiffness in Electrodes for Lithium Ion Batteries
Authors: Gewirth Andrew A. , Tavassol Hadi , Jones Elizabeth M. C. , Sottos Nancy R. 
Published: February 2020

Higher power and charging rates are essential for large scale adoption of lithium-ion batteries in transportation applications. While lithium-ion batteries are ubiquitous in portable electronics, their performance and lifetime suffer during high rate charging and high power discharging. In such extreme electrochemical conditions, the mechanical response of electrode materials governs their degradation behavior. Here, we present a new technique to probe the electrochemically-induced mechanics of electrodes by calculating the electrochemical stiffness of electrodes via coordinated in situ stress and strain measurements. Through the electrochemical stiffness, we elucidate inherent and rate-dependent mechanical responses of graphitic battery electrodes. We find that stress and strain are asynchronous as shown in the figure. In particular, stress development is found to lead strain development as different graphite-lithium intercalation compounds are formed. Additionally, our analysis reveals inversely scaled rate-dependent behaviors for stress and strain responses. Stress scales as scan rate while strain scales with charge (or, equivalently, capacity). These measurements provide a new paradigm for understanding mechanical effects in intercalation systems, such as batteries. Stress arises as resistance to lithiation, while strain arises as a consequence of lithiation. Electrochemical stiffness measurements provide new insights into the origin of the rate-dependent chemo-mechanical degradations, and provide a probe to evaluate advanced battery electrodes.
Electrochemical stress measurements are also utilized to interrogate diverse processes in Li ion battery materials, among them the response of Sn materials to lithiation and delithiation.
Investigation of Aluminum Environments in Li-Ion Cathode NCA and Al-Doped NMC Via 27al MAS NMR Spectroscopy
Authors: Dogan Fulya , Key Baris , Iddir Hakim , Vaughey John T. 
Published: February 2020

Application of aluminum based coatings and partial aluminum substitution for transition metals (doping) are commonly used in lithium ion batteries to improve electrochemical performance and chemical stability of the cathode systems by modifying the surface of cathode materials, increasing the operating voltages, enhancing thermal stability of the material, and reducing metal dissolution. However understanding the nature of surface and lattice aluminum environments or understanding possible aluminum diffusion in to the interphase have been a challenge for aluminum bearing Li-ion battery materials such as LiNi1-y-zCoyAlzO2 (NCA), aluminum doped LiNixMnyCozO2 (NMC) and coated layered metal oxides. 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is one of the few structural probes currently available that can qualitatively and quantitatively characterize lattice and non-lattice (i.e. surface, coatings, segregation, secondary phase etc.) aluminum coordinations. In the present study, we use NMR to gain new insights into transition metal (TM)-O-Al coordiations and evolution of lattice aluminum sites upon cycling. In each case, aluminum coordination of paramagnetic (lattice) and diamagnetic (non-lattice) nature have been investigated and their respective evolutions upon cycling reported.
New Polymeric Materials for Li-Ion Batteries: Poly(phenoxy-ketimine)s
Authors: Demir Haci O. , Berkem Ali S. , Bas Gamze , Cakmak Mukerrem 
Published: February 2020

Lithium-ion batteries (LIBs) are in great demand as energy sources for many applications and research towards finding new materials to improve the performance is underway. Advances in active chemistry are left to the solid-state chemists’ creativity and innovation in the design and elaboration of new intercalation electrodes. Many of the organic compounds are limited by their thermal stability, rate capability, cycle life and low energy density values. Tarascon and co-workers have rekindled interest in the area of organic electrodes by proposing highly conjugated carboxylates, pyromellitic diimides, benzoquinone derivatives, oxocarbonyls, etc. as electrodes for Li-ion batteries.1In the case of poly(phenoxy-ketimine)s, they have been recognized that molecules with hydroxyl and ketimine pendant groups in conjugation with aromatic systems may be efficient organic electrodes. In this study, we report the usage of poly(phenoxy-ketimine)s, a potentially low-cost, eco-friendly, simple synthesis process, as organic electrode materials in Li-ion batteries (Scheme 1).
References:
1. M. Armand, S. Grugeon, H. Vezin, S. Laruelle, P. Ribiere, P. Poizot and J. M. Tarascon, Nat. Mater., 2009, 8, 120.

Scheme 1.The structure of the poly(phenoxy-ketimine)s

Figure 1
Performance and Safety Characteristics of Si-Based Anode Materials for Li-Ion Batteries
Authors: Yanagida Masahiro , Mukai Takashi , Ikeuchi Yuuta , Sakamoto Taichi , Yamashita Naoto , Tanaka Hideaki 
Published: February 2020

Silicon is one of promising active materials for Li-ion batteries for its high capacity. In order to utilize silicon-based materials as alternative anode, the composite electrodes were prepared from silicon-based materials with various binders (such as acrylic acid, polyimide), conducting materials (AB, CB) and current collecting materials. Pouch cells were composed with the electrode and various separator. To investigate the electrochemical properties of the silicon-based materials anode, an electrochemical test was conducted. From the view point of the safety characterization compared with electrode resistance, the results of nail insertion test for pouch cells were also carried out. In this study cycle performance was heavily dependent on the binder.
Effects of Biopolymer-Binder Crosslinking on Silicon Anode Performance
Authors: Dufficy Martin K , Dennis Kimberly A , Khan Saad A , Fedkiw Peter S 
Published: February 2020

Silicon-based electrodes offer charge capacities much greater than graphite, however, short-cycle life stymies commercialization of Si in Li-ion batteries (LIBs). Binding agents plays a crucial role in Si-electrode performance; binder composition induces interactions/reactions with Si and electrolytes that greatly influence cycling performance of Si-based systems. Thus, elucidation of such interactions and reactions is paramount to extend cycle life and increase capacity. We previously reported on usage of guar gum (GG) as a novel binding agent for Si nanoparticle (SiNP) electrodes [1]. Electrodes using GG binders retain >70% capacity after 250 cycles and outperform carboxymethyl-bound Si electrodes. Nevertheless, shortcomings in SiNP/GG system include 1) low ionic and electronic conductivity and 2) fractured, and possibly delaminated, composite electrodes. To overcome these shortcomings, we developed a novel gel binder in which a conductive additive was reinforced within the binder.
The novel gel binder comprises crosslinked GG/carbon black (CB) dispersions. We first probed network formation via dynamic rheology, which revealed greater moduli for the GG/CB system than in the absence of CB, and suggests that CB particles enhance network strength through physical crosslinks (Figure 1a). In attempt to elucidate the role of the binder in Si-based electrodes, we investigated the influence of reaction time (or crosslinking density) on physical properties such as elasticity, electrolyte uptake, ionic conductivity, and adhesion. Physical properties could then be correlated with electrochemical performance in Li-ion half-cells. We found that marginally-crosslinked GG/CB binders in SiNP electrodes led to enhanced cycling performance, whereas capacity was limited in SiNP electrodes using densely-crosslinked GG/CB binders. Symmetrical charge/discharge cycling at 3.6 A g-1 revealed SiNP electrodes with marginally-crosslinked GG/CB binders have larger capacities than non-crosslinked binders (Figure 1b), which may be attributed to electronically conductive networks of CB. Additionally, capacity retention increased with crosslinking of binders (Figure 1b), which may be attributed to preservation of initial electrode microstructure. In attempt to enhance Si electrode feasibility in commercial LIBs, the ensuing study provides fundamental relations between crosslinked-biopolymer binders and SiNP electrode performance.

Figure 1. (a) Evolution of storage modulus, G’, in GG systems with CB (blue) and without (black) using measurements from dynamic stress sweeps; (b) Capacities over 200 cycles of SiNP electrodes using various GG/CB-binder crosslinking densities at 3.6 A g-1

Reference
[1] J. Mater. Chem. A, 2015, 3, 12023-12030

Figure 1
In Situ EXAFS Study of Tin Phosphide/Graphite Composite Anodes for Lithium-Ion Batteries
Authors: Ding Yujia , Li Zhe-Fei , Segre Carlo U , Wang Yuxuan , Botte Gerardine G 
Published: February 2020

Lithium-ion batteries (LIBs) have become the primary power source for portable electronics and hybrid and electric vehicles. The rapid growth applications of LIBs require significant improvement in their capacity, energy density and cycle life. Sn-based materials are alternatives to replace the traditional most widely used anode material, graphite, which only offers a capacity of 372 mAh/g. Metallic tin or tin oxide can achieve initial capacities over 1000 mAh/g. However, these materials suffer from volume expansion and formation of irreversible phases during lithiation that degrade the capacity and battery performance rapidly. A layered structure material tin phosphide (Sn4P3) is a promising anode material with a high initial capacity of over 1200 mAh/g. Lithiation of Sn4P3 starts with a conversion reaction that forms metallic tin and lithium phosphide, followed by a lithium-tin alloying reaction. Although Li3P is a better lithium-ion conductor than Li2O, Sn4P3 still suffers from a large volume change during the initial lithiation and the irreversible formation of Li3P.
This study focuses on the characterization of Sn4P3 and Sn4P3/graphite composites synthesized by high-energy ball milling using red phosphorus and tin nanoparticles under Ar atmosphere. The capacity of pure Sn4P3 rapidly decreases to around 200 mAh/g after 15 cycles. In contrast, Sn4P3/graphite composites exhibit excellent electrochemical performance and durability with a capacity of 610 mAh/g at 0.4 C after 100 cycles. In addition, the coulombic efficiency was also much higher in the Sn4P3/graphite composites, indicating a reversible lithiation/delithiation behavior and more stable SEI layer formation.
In situ extended x-ray absorption fine structure (EXAFS) measurements were performed to study the local environment changes around Sn atoms during the lithiation/delithiation process. EXAFS scans of the cell were taken continuously and were analyzed as a function of different charged and discharged states. It is evident that the local Sn environment in the Sn4P3/graphite composite is fully reversible on lithiation/delithiation while the local Sn environment of pure Sn4P3 changes irreversibly after several cycles consistent with the electrochemical results. A mechanism for performance degradation of Sn4P3 and cycling durability of Sn4P3/graphite composites is proposed based on modeling of the EXAFS data.