bluuebunny/crossref_metadata_2025 huggingface dataset:
Invited Presentation: Research on Nano-Si/C Nanocomposites as Anode for Li-Ion Batteries
Authors: Luo Fei , Chu Geng , Li Hong , Chen Liquan , Huang Xuejie
Published: February 2020

Nanosized silicon has been paid much attention as high capacity anode materials for Li-ion batteries since our first report in 1999. The main challenge for Si anode is the large volume variation during lithium insertion and extraction, which shows a linear dependence on the capacity. Several problems are caused consequently: 1) the total specific capacity of anode has to be limited due to fairly strict restriction on volume variation of batteries during operating, especially for tablet devices. Thus, the advantages of the high theoretical capacity and the volumetric energy density are not as significant as expected. 2) The solid electrolyte interphase (SEI) on the surface of silicon is not as stable as graphite and could be very thick, which consume lithium from cathode and nonaqueous electrolyte irreversibly, leading to low columbic efficiency, capacity fading, increase of internal resistance and gas release. 3) Nanosized silicon particles tend to agglomerate or merge into big pieces and follow further cracking, leading to the formation of the SEI on freshed surface and the loss of electronic contact for active particles. In order to solve above problems, great efforts have been paid and many strategies have been considered. Among them, SiOx, amorphous Si alloy and nano-Si/C composite are more promising for practical application in view of the electrochemical performances and cost.

In this report, we will summarize our investigation on the formation of very thick solid electrolyte interphase (SEI) on naked silicon anode at low rate, direct 3Dvisualization of multiple layer structured SEI. The optimization on additive, binder and microstructure for controlling interfacial properties and maintaining the structure stability of nano-Si/C composite anodes will be reported.

Acknowledgment: Financial support from CAS project (KJCX2-YW-W26), "Strategic Priority Research Program" of the Chinese Academy of Sciences,Grant No. XDA09010102 and National project 973 (2012CB932900) are appreciated.
Invited Presentation: Li-S Batteries and Beyond Systems: Electrochemistry and Materials Design
Authors: Guo Yu-Guo
Published: February 2020

There is no doubt that the pursuit of advanced energy storage devices with higher energy densities is critical for powering our future society.[1,2] Among the best candidates for next-generation high-energy-storage systems, alkali metal-chalcogen batteries, including Li-S, Li-Se, and Na-S systems hold high theoretical energy densities, making them especially attractive. Here, we report the recent progress in this field starting from Li-S batteries. We discuss the electrochemistry of Li-S batteries with different sulfur allotropies,[3] the recent advances in S cathodes, Li anodes, electrolytes, as well as the new designs of Li-S pouch cells (5~10 Ah).[4] Secondly, we report advanced selenium-carbon cathodes for rechargeable Li-Se batteries, as well as the selenium molecules evolution upon cycling.[5] Finally, through employing the confined chain-like sulfur molecules as the active cathode component for room-temperature Na-S batteries, a novel mechanism is proposed and verified for the batteries’ electrochemistry, which bringing a tripled specific capacity and an increased specific energy compared to traditional high-temperature Na-S batteries.[6]

References

[1] Y.-G. Guo, J.-S. Hu, L.-J. Wan,
Adv.

Mater.

2008, 20, 2878

[2] S. Xin, Y.-G. Guo, L.-J. Wan,
Acc. Chem. Res. 2012, 45, 1759

[3] S. Xin, L. Gu, N. Zhao, Y. Yin, L. Zhou, Y.-G. Guo, L.-J. Wan,
J. Am. Chem. Soc. 2012, 134, 18510

[4] Y. X. Yin, S. Xin, Y.-G. Guo, L.-J. Wan,
Angew. Chem. Int. Edit. 2013, 52, 13186

[5] C.-P. Yang, S. Xin, Y.-X. Yin, H. Ye, J. Zhang, Y.-G. Guo,
Angew.

Chem. Int.

Edit.

2013, 52, 8363

[6] S. Xin, Y.-X. Yin, Y.-G. Guo, L.-J. Wan,
Adv. Mater.

2014, DOI: 10.1002/adma.201304126, in press
Invited Presentation: Non Lithium Based Technologies: Walking on the Sodium Side
Authors: Palacin M Rosa
Published: February 2020

The development of room temperature sodium based batteries is currently a challenge in fundamental materials research. While it holds promise for accelerated development thanks to the knowledge gained in the “chemically similar” Li-ion ubiquitous technology, the Na-ion technology is still in its infancy. Proof of concept was given long ago1
,
2 but it is only recently that the topic has recaptured the attention of the scientific community concomitant to large scale development of the Li-ion technology and concerns about lithium cost and availability.3
,
4
,
5
Since Na-ion batteries do not involve the use of sodium metal anodes, there would be no a priori reason to think that they cannot attain the same performances than Li-ion if suitable positive and negative electrode materials are developed.

The talk will review recent research aiming at the development of negative electrode materials discussing analogies and differences between lithium and sodium systems.6,7,8 Results will also be presented dealing with systematic studies on electrolytes and formulation and assembly/performance of laboratory full Na-ion cells.9,10

References

[1] L.W. Shacklette, T.R. Jow, L. Townsend, J. Electrochem. Soc. 135 (1988) 2669.

[2] Y. Ma, M.M. Doeff, S.J. Visco, L.C. De Jonghe, J. Electrochem. Soc. 140 (1993) 2726–2733.

[3] V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-González, T. Rojo, Energy Environ. Sci. 5 (2012) 5884.

[4] M.D. Slater, D. Kim, E. Lee, C.S. Johnson, Adv. Funct. Mater. 23 (2013) 947.

[5] S.W. Kim, D.H. Seo, X. Ma, G. Ceder, K. Kang, Adv. Energy Mater. 2 (2012) 710.

[6] P. Senguttuvan, G. Rouse, V. Seznec, J.M. Tarascon, M.R. Palacín, Chem. Mat. 23 (2011) 4109.

[7] A. Ponrouch, A.R. Goñi, M. R. Palacín. Electrochem. Comm. 27 (2013) 85.

[8] G. Rousse, M.E. Arroyo de Dompablo, P. Senguttuvan, A. Ponrouch, J.M. Tarascon, M.R. Palacín, Chem. Mat. 25 (2013) 4946.

[9] A. Ponrouch, E. Marchante, M. Courty, J.M. Tarascon, M.R. Palacín, Energy Environ. Sci. 5 (2012) 8572.

[10] A. Ponrouch, R. Dedryvère, D. Monti, A.E. Demet, J.M. Ateba Mba, L. Croguennec, C. Masquelier, P. Johansson, M.R. Palacín, Energy Environ. Sci. 6 (2013) 2361.
Invited Presentation: Microstructured Nanomaterials for Lithium-Ion Battery Anodes
Authors: Passerini Stefano , Bresser Dominic
Published: February 2020

The tremendous success of lithium-ion batteries as power source for portable electronic devices since their first commercialization in 1991, marking a breakthrough in battery technology, has rendered them as the most promising energy storage devices for hybrid and, most likely, fully electric vehicles. However, further improvement in terms of energy and power density is still needed in order to meet the demands of modern society’s transportation requirements.

Particularly with respect to the anode side, recent research activities have shown the great benefit of nanostructuring the active material particles in order to combine high rate performance and large specific capacities for alternative anode materials, especially those undergoing rather large volume changes upon (de-)lithiation. However, nanosized particles suffer several safety, health, and processability issues.

We have recently proposed several composites of carbon and nanomaterials as alternative anodes in lithium-ion batteries. Several examples of micro-structured, insertion, alloying, and conversion-alloying nanomaterials will be presented, showing an enhanced performance compared to “simple” nanoparticles only.
Functionalized Graphene Cathode for High Energy and Power Na Rechargeable Batteries
Authors: Kim Haegyeom , Park Young-Uk , Park Kyu-Young , Lim Hee-Dae , Hong Jihyun , Kang Kisuk
Published: February 2020

Developing low-cost and high-performance energy storage devices is important for sustainable energy utilization. Recently, sodium (Na) ion batteries have been highlighted as a possible competitor to lithium (Li) ion batteries because of their potential merit in the cost effectiveness. Na resources are earth-abundant, and Na electrochemistry shares many similarities with Li. However, their relatively low energy/power densities and unreliable cycle stability need to be addressed. In this work, we propose a novel high-performance cathode for Na rechargeable batteries based on functionalized graphene nanoplatelets. Starting from natural graphite, functionalized graphene nanoplatelets were fabricated via simple scalable routes, which could control the chemical composition and porous nanostructure of the sample in one-step. By using surface reactions between Na and functionals on graphene nanoplatelets, (i) no significant lattice change occurred during battery cycling, and (ii) much faster Na kinetics could be achieved through porous network without solid-state diffusion.[1] Furthermore, the high electrical conductivity of the material could aid in improving the rate capability.[2] While previous studies of graphite-based electrodes are mostly found in anode applications for NIB and only very recently its cathode application was discovered, [3, 4] this work manipulated the carbon into a cathode with a tunability of composition and nanostructure by simple one-step chemical modification. The functionalized graphene cathode could deliver the energy of ~500 Wh kg-1 without capacity decay during 300 battery cycles and could also exhibit an unprecedentedly high power of ~55 kW kg-1with a less-than-10 s charge/discharge rate for NIB.

References

[1] H. Kim, H.-D. Lim, S.-W. Kim, J. Hong, D.-H. Seo, D.-c. Kim, S. Jeon, S. Park, K. Kang, Sci. Rep., Scalable Functionalized Graphene Nano-platelets as Tunable Cathodes for High-performance Lithium Rechargeable Batteries 3 (2013) 1506.

[2] S.-M. Oh, S.-T. Myung, J. Hassoun, B. Scrosati, Y.-K. Sun, Electrochem. Commun., Reversible NaFePO4electrode for sodium secondary batteries 22 (2012) 149-152.

[3] Y.-X. Wang, S.-L. Chou, H.-K. Liu, S.-X. Dou, Carbon, Reduced graphene oxide with superior cycling stability and rate capability for sodium storage 57 (2013) 202-208.

[4] Z. Wang, L. Qie, L. Yuan, W. Zhang, X. Hu, Y. Huang, Carbon, Functionalized N-doped interconnected carbon nanofibers as an anode material for sodium-ion storage with excellent performance 55 (2013) 328-334.
Binder-Free Thick-Film Anodes of Si Coated with Rutile-Type TiO2
Authors: Usui Hiroyuki , Wasada Kuniaki , Shimizu Masahiro , Sakaguchi Hiroki
Published: February 2020

As an anode material for high-performance Li-ion battery, we have synthesized composites of rutile-type TiO2 and Si by a facile sol-gel method because we focus that a fast Li-ion diffusion in TiO2 can improve a slow kinetics of Li-ion transfer in Si anode. We have investigated anode performance of binder-free thick-film electrodes prepared by a gas-deposition method using the TiO2/Si composites obtained. This method has a unique advantage: essential electrochemical reactions of only active materials can be evaluated because the thick-film electrodes do not include any binder and conductive additive.

Electrode performance as Li-ion battery anode was evaluated in beaker-type there-electrode cells using the TiO2/Si electrodes as working electrodes and Li sheets as counter and reference electrodes. The electrolyte was LiClO4dissolved in propylene carbonate at a concentration of 1 M. Galvanostatic charge–discharge tests were carried out using an electrochemical measurement system at 303K.

X-ray diffraction analysis and field-emission scanning electron microscopic observations revealed that the Si surface of the composites was uniformly covered by rutile TiO2 nanoparticles with 10–50 nm in size. Charge–discharge curves were measured for the TiO2/Si composite electrodes with weight ratios of 43/57 wt.% and 66/34 wt.%. For every electrode, we clearly observed potential plateaus in the charge (lithiation) and discharge (delithiation) processes at 0.05 V and 0.45 V vs. Li/Li+ at the first cycles. These potential plateaus are attributed to the alloying/dealloying reactions of Li–Si. After the second cycles, the charge plateaus inclined and rose to 0.1–0.2 V vs. Li/Li+, which has been explained as resulting from amorphization of Si at the first cycle and its single-phase reaction with Li+in the subsequent cycles. The electrodes behaved very alike until the 100th cycle.

Figure 1 shows cycling performances of the TiO2/Si composite electrodes. The initial discharge capacities of 1500 and 790 mA h g−1 were obtained for the TiO2/Si electrodes of 43/57 wt.% and 66/34 wt.%. These capacities correspond to capacities per Si of 2500 and 2100 mA h g(Si)−1. The composite electrode of TiO2/Si (43/57 wt.%) exhibited a remarkably improved cyclability at a current rate of 1.6C: the discharge capacity of 710 mA h g−1 (1170 mA h g(Si)−1) could be achieved even at the 900th cycle. In addition, the electrode showed a specific capacity per Si weight was as large as 1870 mA h g(Si)−1 even at a high current rate of 4.8C, whereas an Si electrode showed the comparable capacity at a low rate of 1.6C. It is considered that a fast Li-ion diffusion in TiO2 provides smooth insertion/extraction of Li-ion into/from the composite electrodes. The results offer a utility of rutile TiO2 as a Li-ion conductor in Si-based electrodes for the next-generation Li-ion battery.
Recent Progress for Room-Temperature Stationary Sodium-Ion Batteries
Authors: Hu Yong-Sheng
Published: February 2020

In the energy storage field, lithium-ion batteries have been extensively explored as power sources for various types of important applications, such as portable electronic devices, electrical vehicles, etc. Due to the low abundance of lithium in the Earth’s crust (0.0065%), large-scale applications of lithium-ion batteries become questionable, especially if low cost and high efficient recycling technology could not be developed. Alternatively, room-temperature sodium-ion batteries, which were originally investigated in parallel with lithium-ion batteries, have again aroused interest particularly as stationary batteries for large-scale electrical energy storage in the applications of renewable energy and smart grid owing to a large abundance (2.75%) of sodium resources and potentially low cost, for which the demanding on energy densities of the power sources is not so seriously.

In this contribution, I will present our recent work on several cathode and anode materials including Na3V2(PO4)3/C [1,2], Li3[LiTi5]O12 [3,4,5], zero-strain P2-Na0.66[Li0.22Ti0.78]O2 [6], Na2Ti3O7 [7], Na2C8H4O4 [8] and hard carbon sphere (HCS) [9] as well as a new electrolyte system for room-temperature stationary sodium-ion batteries [10]. Several full cells based on our developed cathode and anode materials will also be demonstrated.

References

[1] Z. L. Jian, L. Zhao, H. L. Pan, Y.-S. Hu, H. Li, W. Chen, L. Q. Chen,
Electrochem. Commun
., 2012, 14, 86-89.

[2] Z. L. Jian, W. Z. Han, X. Lu, H. X. Yang, Y.-S. Hu, J. Zhou, Z. B. Zhou, J. Q. Li, W. Chen, D. F. Chen, L. Q. Chen,
Adv. Energy Mater.
, 2013, 3, 156-160.

[3] L. Zhao, H. L. Pan, Y.-S. Hu, H. Li, L. Q. Chen,
Chin. Phys. B
, 2012, 21, 028201.

[4] Y. Sun, L. Zhao, H. L. Pan, X. Lu, L. Gu, Y.-S. Hu, H. Li, M. Armand, Y. Ikuhara, L. Q. Chen, X. J. Huang,
Nature Communications
, 2013, 4, 1870.

[5] X. Q. Yu, H. L. Pan, W. Wan, C. Ma, J. M. Bai, Q. P. Meng, S. N. Ehrlich, Y.-S. Hu, X.-Q. Yang,
Nano Lett
., 2013, 13, 4721.

[6] Y. S. Wang, X. Q. Yu, S. Y. Xu, J. M. Bai, R. J. Xiao, Y.-S. Hu, H. Li, X.-Q. Yang, L. Q. Chen, X. J. Huang,
Nature Communications
, 2013, 4, 2365.

[7] H. L. Pan, X. Lu, X. Q. Yu, Y.-S. Hu, H, Li, X.-Q. Yang, L. Q. Chen,
Adv. Energy Mater
., 2013, 3, 1186-1194.

[8] L. Zhao, J. M. Zhao, Y.-S. Hu, H. Li, Z. B. Zhou, M. Armand, L. Q. Chen,
Adv. Energy Mater
., 2012, 2, 962-965.

[9] J. Z. Yu, Y. S. Wang, H. L. Pan, L. Zhao, Y.-S. Hu, H. Li, L. Q. Chen, in preparation.

[10] H. L. Pan, Y.-S. Hu, L. Q. Chen,
Energy Environ. Sci
., 2013, 6, 2338-2360.

Figure 1
Typical discharge/charge curves of the proposed materials for room-temperature sodium-ion batteries
Investigation of NaxMn0.5Fe0.5O2 Cathode Materials from Low Cost Preparation Routes
Authors: Salamone Matteo , Ruffo Riccardo , Longoni Gianluca , Mari Claudio Maria
Published: February 2020

The wide use of lithium in rechargeable batteries has made it strategic and expensive and therefore different approaches have been recently investigated to overcome this issue. Even though sodium has higher atomic weight, higher oxidation potential and bigger ionic radius than lithium, it can be a valuable alternative in less weight/volume-sensitive applications because of its wider availability and lower costs. At the present, the most promising sodium systems use a transition metal oxide and hard carbon as positive and negative electrode, respectively. In this configuration, considering the material specific capacity and the discharge profiles, the battery could be reasonably able to display an energy density of about 70-80% of lithium analogous with unexplored power density. However, several polycrystalline compounds show lower diffusivity barrier for Na+ compared to Li+ homologous structures. Among the oxide materials, different phases have been proposed like NaCrO2, NaxCoO2, NaxMnO2, and NaxMn0.5Fe0.5O2showing capacity about 100-150 mAh/g in the potential range from 2.0 to 4.0 V vs. metallic sodium with good kinetic. In particular, the Na0.67[Fe0.5Mn0.5]O2P2 structure has received significant attention due to the presence of the relative inexpensive and environmental friendly Mn and Fe in the structure.

We report here two different low cost methods to prepare Na0.67[Mn0.5Fe0.5]O2 (NMFO); the former route is based on sol gel approach from acetate precursors in methanol while the latter one on the use of cotton as template agent. The suitable chemical precursors as well as the thermal treatment procedures were carefully selected after TGA/DSC analysis of various reaction mixtures. The resulting phases have been structural characterized by XRPD with Rietveld analysis which reveals that a small amount of hematite (< 5%) is present in both samples. The morphological analysis by SEM and TEM confirm the good crystallinity and show the characteristic platelet shape having several mm largeness and few hundred nm thickness. The electrochemical characterization was performed in 3 electrode Swagelock type cell using metallic sodium as both counter and reference electrode and a 1M solution of NaClO4in EC:DMC 1:1 + FEC 2% as electrolyte. The charge discharge profiles show the two characteristic plateau at low (2.3/2.7 V) and high potential (3.6/4.0 V) vs. metallic sodium. The galvanostatic cycling results (see Figure 1, sol gel material) reveals a reversible specific capacity of about 120, 110, and 60 mAh/g at current rates of C/20, C/10, and C/2, respectively.

In conclusion, both low cost methods are able to produce micrometric sized NMFO materials with good electrochemical properties as cathodes in sodium ion battery.
Solvothermal Synthesis of Co3S4/Graphene Nanoassemblies As Anode Materials for Lithium-Ion Batteries
Authors: Xie Xiuqiang , Su Dawei , Huang Xiaodan , Dou Shi Xue , Wang Guoxiu
Published: February 2020

Co3S4/graphene nanoassemblies were synthesized by a facile solvothermal approach, in which bifunctional dimethyl sulfoxide served as both solvent and sulfur-source. Structural characterizations reveal an intimate contact between Co3S4 and graphene matrix. When employed as anode materials for lithium-ion batteries, the Co3S4/graphene nanoassemblies exhibited good electrochemical performance, including a high reversible capacity of 1085 mAh/g, good cyclability and excellent rate capability. Compared to bare Co3S4 and graphene, the lithium-ion storage performance has been significantly improved. The improved electrochemical performance for reversible lithium-ion storage could be ascribed to the synergistic effects of the Co3S4/graphene nanoassemblies as an integrated hybrid nanoarchitecture, in which graphene nanosheets provide electronic conductivity, serve as the homogeneous dispersive agent and offer buffer layers for the active Co3S4 during lithium-ion insertion and extraction processes.
Facile Way to Synthesis of Nanocable-like Electrode Materials for High-Performance of Lithium-Ion Batteries
Authors: Wang Bin , Cheng Jianli , Nie Fude
Published: February 2020

Recently, One-dimensional (1D) CNT@ metal oxide coaxial nanocomposites with controlled size and chemical composition have attracted particular interests because of their superb lithium storage capability provided by their unique structure.1-3 However, so far these reported synthetic approaches usually involve multiple time-consuming procedures, toxic chemicals, and encounter nonuniform morphology problem.

In this report, we present a simple and green one-pot route to form a new nanostructured CNT@ metal oixdes-C nanocable by using glucose as structure-directing agent and carbon source without any prerequisite for covalent/ non-covalent functionalization of CNTs. Although glucose is often used as a carbon source in hydrothermal reactions,4,5 it is the first time to be used as a structure-directing agent to form CNT@ metal oxides-C nanocable.

This simple and green approach can be used for the fabrication of metal oxide/CNT nanocomposites, including but not limited to CNT@TiO2-C nanocable, CNT@Fe3O4-C nanocable, CNT@SnO2-C nanocable (showing in Figure 1). Due to the synergistic effect of the high electronic conductivity support and the inner CNT/outer carbon buffering matrix, the nanocables show improved lithium storage behavior when used as anode materials. For example, The CNT@TiO2-C nanocables show remarkable rate capability with reversible charge capacity of 210,178 and 127 mAh g-1at 10C, 20C and 50C, respectively (showing in Figure 2), as well as excellent high rate cycling stability with a capacity retention of 87% after 2000 cycles at 50C.

In summary, by using a simple synthesis method and low cost starting materials, it is now possible to prepare sandwiched CNT@ metal oxdies-C nanocables for high performance of LIBs. We anticipate that the one-pot synthesis method proposed in this study will provide more choices for addressing the problems of LIBs. This talk will further describe testing and capabilities of these materials.

Reference

1. M. Sathiya, A. S. Prakash, K. Ramesha, J. M. Tarascon and A. K. Shukla, J Am Chem Soc, 2011, 133, 16291-16299.

2. F. F. Cao, Y. G. Guo and L. J. Wan, Energ Environ Sci, 2011, 4, 1634-1642.

3. A. L. M. Reddy, M. M. Shaijumon, S. R. Gowda and P. M. Ajayan, Nano Lett, 2009, 9, 1002-1006.

4. X. W. Lou, J. S. Chen, P. Chen and L. A. Archer, Chem Mater, 2009, 21, 2868-2874.

5. X. M. Sun and Y. D. Li, Angew Chem Int Edit, 2004, 43, 597-601.
Effect of Conductive Agent on Electrochemical Properties of Next Generation Lib
Authors: Itoh Tetsuya , Yoda Akira , Nako Yuki , Saito Tatsuya , Sonoda Takashi , Yokota Hiroshi
Published: February 2020

Introduction

In general, the carbon black (CB) such as furnace black (FB) and acetylene black (AB) have been used as conductive agent for lithium ion battery (LiB). Recently, the powder properties of them seem to be very similar. Very recently towards next-generation high energy density LiB, various approaches has been reported.1,2In such high energy density application, the amount of conductive agent tends to be reduced as much as possible. However, by the present, there have been very few reports on conductive agent, in older to possess sufficient conductivity even in less amount of conductive agent. In this study, the influence of the carbon black as conductive agent on electrical performance has been investigated. Moreover, the mechanism was considered from the view of morphology inside electrodes.

Experimental

Conductive agents were prepared various CBs that were synthesized by different production method and morphology such as AB and FB. For fabricate cathode electrode, LiNi0.5Mn0.3Co0.2O2as cathode active material, CB and PVdF have been made kneading with a mass ratio of 95: 3: 2. The obtained electrode has been set in a simple SUS two-pole cell, and then electronic resistance was measured by impressing direct current electricity. The fundamental electrochemical performances were evaluated by using system Li metal | 1M LiPF6/ECand DEC(3:7 vol%) | positive electrode(2032 type coin cell). For investigating the morphology of positive electrode, SEM (JSM-7000,JEOL) performed observation of the electrode surface and cross section.

Result and Discussion

Table 1 shows powder properties of conductive agent. Fig. 1 shows the powder characteristics of CB have influenced on the rate properties. AB1 had superior rate properties as compared to the other CBs. Fig. 2 shows the SEM images of the electrode cross section using AB1 and AB2. The electrodes fabricated with AB1 had homogeneous microstructure, while the electrodes fabricated with AB2 had heterogeneous because of agglomeration of AB and PVdF(Black contrast area). These results imply that the electrode with more homogeneous microstructure had superior rate property. In particular, since the amount of conductive agents should be decreased to achieve higher energy density of LiB, the dispersibility(= homogeneous microstructure electrode) of CB and PVdF might be more important than those in previous LiB. To decrease agglomeration of CB and PVdF, it is needed to choose optimized CB. In this study, all the electrodes have been fabricated by same PVdF, so that the dispersibility of electrodes might be mainly affected by the CB powder characteristics. The other CBs that have various morphology have been analyzed. Further result and discussion in detail will be presented on the day of meeting.

Reference

T. Ohzuku at al., J. Mater. Chem., 21, 10179 (2011).

A. R. Armstrong, et al,. J. Am. Soc., 128, 8694 (2006).
Three-Dimensional Silicon/Carbon Core-Shell Electrode As an Anode Material for Lithium-Ion Battery
Authors: Kim Jung Sub , Kohler Robert , Pfleging Wilhelm , Seifert Hans Jürgen , Byun Dongjin , Jung Hun-Gi , Lee Joong-Kee
Published: February 2020

The high-performance materials used for lithium ion batteries include Si-based materials which are some of the most promising materials for electrodes in large rechargeable batteries because of their exceptionally high gravimetric capacity (3,572 mAh/g), low redox potential between 0.2 and 0.4 V (vs. Li/Li+) and low reactivity with non-aqueous electrolyte. Practical application of silicon anodes with huge capacity for lithium ion batteries has so far been mainly hindered due to its low electrical conductivity and large volume change (ca. 400 %) generating during the lithiation and delithiation process [1]. Thus, surface engineering for particles (active material design) and modification for electrode structure (electrode design) of silicon are necessary to alleviate these critical limiting factors. The silicon/carbon core-shell particles (Si@C, active material design) were prepared by thermal chemical vapor deposition and subsequent three-dimensional electrode (electrode design) with channel width of 30 µm using laser technique. The electrochemical characteristics of three-dimensional Si@C employed as anode material for lithium-ion batteries were investigated in order to find effects of material and electrode design. The introduction of carbon coating and laser structuring was achieved the enhanced performance of Si anode materials exhibiting high specific capacity (>2,000 mAh/g), good rate capability and stable cycling (>95% over 50 cycles). The morphology of core-shell having 3D channel could minimize the volume expansion by adoption of void space during repeated cycling.

[1] D. Larcher, S. Beattie, M. Morcrette, K. Edström, J.-C. Jumas and J.-M. Tarascon, J. Mater. Chem. , 17, 3759 (2007).
Mesoporous Lithium Titanate-Carbon Composite (Li4Ti5O12-Carbon) with Controlled Microstructure As Anode in Lithium Ion Batteries for Wide Temperature Range
Authors: Li Chi-Ying Vanessa , Ho Ching-Kit , Yung Hoi , Chan Kwong-Yu
Published: February 2020

The high discharge rate performance of lithium titanate (Li4Ti5O12) is limited by the low electronic conductivity of the material (< 10-11 Sm-1), addition of carbon is one of the effective way in enhancing the rate performance. [1-4]

In this study, carbons with a hollow core and mesoporous shells of controlled dimensions (in terms of diameter of core, thickness of the shell and diameter of the mesopores) were synthesized via silica hard-template method (Fig. 1). Li4Ti5O12-carbon composites were built through impregnation of Li4Ti5O12 into the core-shell carbon (Fig. 2). These Li4Ti5O12-carbon composites demonstrate higher electronic conductivity, and enhanced electrochemical behavior for prolonged cycles at high discharge rate due to increased surface area of the active material, and improved ion transport pathways from possibly the length scale effect.

Cross-section TEM studies have been performed and proved that Li4Ti5O12 particles are impregnated within the mesoporous carbon shell structure. (Fig. 3) This Li4Ti5O12-carbon composite can achieve superb coulobmic efficiency of 98% and 96%, and superior long-cycling life with remarkably high capacity retention of 99% and 85% over 2,000 cycles at 10C (2.2 Ag-1) and 20C (4.4 Ag-1), respectively. Similar electrochemical behavior is observed for low temperature condition.

Acknowledgement

This work was supported by Hong Kong Research Grants Council General Research Fund (HKU 700209P), Strategic Research Theme on Clean Energy, University Development Fund on Initiative on Clean Energy, and Innovation and Technology Fund of the Hong Kong SAR (ITS/076/11).

References

C.K. Ho, H. Yung, M. Zhou, C.Y.V. Li, K.Y. Chan, “Mesoporous Lithium Titanate-Carbon Composite with Controlled Microstructure”, Abstract #1148, 224th ECS Meeting, October 2013, San Francisco, U.S.A.

S.W. Ting, C.Y.V. Li, H. Yung. C.K. Ho and K.Y. Chan, “Structural and Electrochemical Studies of Mesoporous Li4Ti5O12-TiO2 Composite Spheres as Anode Material for Lithium ion Batteries, 222nd ECS Meeting, October 2012, Honolulu, Hawaii, U.S.A.

C.Y.V. Li, S.W. Ting, Z. Yang, W. Zhuang, X. Lu, H. Yung and K.Y. Chan, “Lithium Titanate Prepared from Mesoporous TiO2 Fiber as Anode Material for Lithium Ion Batteries, , 222nd ECS Meeting, October 2012, Honolulu, Hawaii, U.S.A.

X. Zheng, C. Dong, B. Huang, M. Lu, Int. J. Electrochem. Sci., 7 (2012) 9869 – 9880.
Electrodeposited Three-Dimensional Porous Silicon Nanostructure with Excellent Stability and High Rate Performance for Lithium-Ion Batteries
Authors: Suk Jungdon , KIM Do Youb , KIM Dong Wook , Kang Yongku
Published: February 2020

Recently, rechargeable lithium ion batteries with higher energy/power densities and better rate performance have been widely developed to be used for powering future portable electronic devices and for application to renewable energy storage facilities and in electric vehicles (EVs)[1]. Silicon is one of the most promising anode candidates owing to its extremely high theoretical capacity of 4200 mAh/g (with the formation of the Li4.2Si alloy), which is more than 10 times higher than the capacity of graphitic carbon (372 mAh/g) and other Li alloys.[2] Due to a major volume change (300-400%) of Si during the lithiation/delithiation processes, the resulting pulverization and a loss of electrical connection between the active materials and the electrode framework cause serious irreversible capacity loss and poor cyclability. In order to solve the pulverization issues of Si, we have fabricated 3D porous Si/metal (copper or nickel) film by an electrodeposition method using two types of template; one is a hydrogen gas bubble template and the other is inverse opal template. Compared with chemical vapor deposition or etching method for porous 3D Si anode, electrodepostion method is a simple and low-cost method which is used for large scale operation in industry.[3] Our 3D porous silicon/metal anode with a well-defined configuration for lithium ion batteries consists of interconnected metal film, which not only allows for robustness during the charge and discharge process with the volume expansion but enables the formation of a large area for silicon electrodeposition at a high capacity in lithium ion batteries. The resulting self-supported 3D porous Si/metal electrodes exhibit a high reversible capacity (2824 mAh/g), remarkable cycling stability (1628 mAh/g after 100 cycles) and superior rate capability without any binder or conductive additives. The results using the 3D porous Si/metal anode in our study represent a promising approach for high-performance silicon-based anodes which are compatible with scaled-up manufacturing process for next-generation lithium-ion batteries due to their simple and rapid fabrication process.

[1] J. Maier, Nature Materials, 2005, 4, 805.

[2] B. A. Boukamp, G. C. Lesh, R. A. Huggins, Journal of Electrochemical Society, 1981, 128, 725.

[3] Y. Nishimura, Y. Fukunaka, Electrochimica Acta, 2007, 53, 111.
New Benzimidazole Nitronyl Nitroxides As Electro-Active Compounds for Battery Electrodes
Authors: Akay Sevda , Esat Burak , Fidan Ismail , Hirel Catherine , Frank Natia
Published: February 2020

Battery systems are energy sources in wide scope of applications such as mobile phones, portable computers, uninterruptible power supplies. Radical bearing organic polymers, also called radical polymers, may be used as cathode- or anode-active materials in batteries. TEMPO (2,2,6,6-Tetramethylpiperidin-1-yl-oxyl) bearing polymers have been synthesized and studied as electrode materials for rechargeable batteries1. In a similar way, benzimidazole nitronyl nitroxides (BNNs) which are nitroxide-containing organic molecules like TEMPO can also be utilized as electro-active materials. Our studies involving synthesis and utilization of these molecules as cathode or anode materials in Li-ion batteries will be presented.

References

1. A Y. Liang , Z. Tao , J.Chen,
Adv. Energy Mater.
2012, 2, 742–769.
A Facile Approach to Prepare Rattle/Hollow-Type α-Fe2O3 Submicron Spheres with a Thin Carbon Layer for High-Performance Lithium Ion Battery Anodes
Authors: Lim Hyung-Seok , Sun Y.-K. , Suh Kyung-Do
Published: February 2020

Recently, the hollow structures of various transition metal oxide materials (cobalt oxides [1], iron oxides [2], nickel oxides [3]) have received particular attention for use in lithium-ion batteries (LIBs) because they not only have a higher theoretical capacity than commercial graphite (372 mAh g-1), but also possess a large void space that can accommodate huge changes in volume during electrochemical reactions. In our previous report, hollow Fe3O4 microspheres exhibited the improvement of cyclability. Although the hollow Fe3O4 microspheres show remarkable improvement in cycling stability, most still exhibited capacity fading at high current rates due to their poor electrical conductivity. In order to improve cycling performance at high current rates, we have prepared rattle/hollow-type α-Fe2O3 submicron spheres with thin carbon layer through the diffusion of metal ions into the hydrogel template. In this synthetic process, an additional carbon coating process is not necessary such as two-step hydrothermal process and chemical vapour deposition (CVD). In addition, we report a strategic synthesis method to control the internal structures of α-Fe2O3 submicron spheres. Of the two types of samples, the rattle-type α-Fe2O3 submicron spheres have a high surface area (1415 m2 g-1) because α-Fe2O3 nano-grains are formed in polymer networks. During removal process of template particles by heat treatment, because the cross-linked networks surrounding tiny Fe metal precursors act as a barrier to prevent particle growth, the rattle structured α-Fe2O3 submicron spheres consisting of nano-sized grains with a high surface area can be formed. In this process, the thin carbon layer is formed on the inside surface as well as outer surface of the α-Fe2O3 nano-grains, which was generated from a decomposition of the polymer templates. These rattle/hollow α-Fe2O3 submicron spheres with thin carbon layer exhibit excellent cyclability at high current rates (~10C). We demonstrated that the void space and thin carbon layer covering most of the α-Fe2O3 surface acts as buffer layer to accommodate variation in the volume of α-Fe2O3 and improves charge transfer at high current rates.

References

[1] J. Wnag, N. Yang, H. Tang, A. Dong, A. Jin, M. Yang, D. Kisailus, H. Zhao, Z. Tang and D. Wang, Angew. Chem. Int. Ed., 2013, 52, 6417.

[2] H. –S. Lim, B. –Y. Jung, Y. –K. Sun, K. –D. Suh, Electrochimica Acta, 2012, 75, 123.

[3] N. H. Idris, J. Mater. Res., 2011, 26, 860.
Dual Performance Electrodes for Li-S and Li-Ion Batteries
Authors: Villevieille Claire , Novák Petr
Published: February 2020

New classes of materials were investigated as potential negative electrodes for Li-ion and Li-S batteries. FeSnS2, Fe2SnS4 and CuSnS2 without any carbon coating were synthetized by solid state reactions. According to their active elements, tin and sulfur, these materials can be cycled in two different potential windows: [0-1V] vs. Li+/Li in the Li-ion system (active window of Sn) and [1.2-2.7V] vs. Li+/Li in the Li-S system (active window of sulfur), using LP30 (1M LiPF6 1:1 EC:DMC) and LiTFSI (1M LiTFSI, 2:1 DME:Diox) as electrolyte, respectively. In both systems, there is a major issue that limits the development of those systems to take into consideration. During cycling of tin particles versus lithium, an alloying process (Snà Li7Sn2) with a volume expansion of 243% of the electrode material takes place, leading to a loss of electric contact in the particles and significant fading. In the Li-S system, lithiation leads to the development of soluble species in the electrolyte (polysulfides) that affect the cycling stability and cause significant fading. For this study, we decided to cycle these materials in two different potential windows and to have a look at the morphology of the electrodes after cycling. By using this approach, we were able to cycle at a rate of 1C (loading of 3-4mg/cm2) for at least 500 cycles and obtained more than 900 mAh/g for the Li-S system and more than 800mAh/g for the Li-ion system, with a coulombic efficiency of around 99%. In both case, the non-active materials (Cu, Fe), as well as S in the active window of Sn, and Sn in the active window of S seemed to be able to buffer both the volume changes of the Sn particles and impede the polysulfide shuttle of the sulfur particles. The impact of the electrolyte on the cycling properties, as well as the role of the electrolyte additive and the different cycling properties will be discussed and compare to the reference sample SnS2 already described in the literature. In situ XRD and post mortem analysis will be further discussed to understand the reaction mechanism of this new promising class of anode materials.
A Novel CuO-Carbon/ Ni-Cu-Mn-Spinel Lithium-Ion Battery
Authors: Verrelli Roberta , Sun Y.-K. , Hassoun Jusef
Published: February 2020

We report here a copper-doped Li0.85Ni0.46Cu0.1Mn1.49O4 high voltage, spinel electrode prepared by an easy, two-step co-precipitation and solid state process. We show that this material adopts an unique morphology characterized by well-developed, crystalline and aggregated micro-particles, that considerably reduces the occurrence of side reactions. This electrode material can operate in a lithium cell at voltages as high as 5.3 V without sign of electrolyte decomposition, delivering a capacity of about 100 mAh g-1 with high retention and high coulombic efficiency over prolonged cycling. By combining Li0.85Ni0.46Cu0.1Mn1.49O4as cathode with a conversion-type, CuO-MCMB anode, a full lithium ion battery exhibiting good performances in terms of voltage (3.4 V), coulombic efficiency (higher than 95%) and stability is obtained.

To the best of our knowledge, such a copper-based battery system is here originally reported. This battery employs sustainable, eco-compatible, low-cost and easily-prepared electrode materials, an additional bonus that makes it particularly suitable for practical exploitation.
A New Free Standing ZnO/MWCNT Nanocomposite Anode Produced By Sol-Gel Spin Coating Method for Li-Ion Batteries
Authors: Köse Hilal , Karaal Seyma , Aydin Ali Osman , Akbulut Hatem
Published: February 2020

Lithium-ion batteries (LIBs) are one of the most popular types of rechargeable battery for portable electronics, with one of the best energy densities, and also the choice power source for electric and hybrid vehicles [1]. Zinc oxide is an attractive material as a potential substitute for the conventional graphite anode in lithium-ion batteries, because the theoretical capacity of ZnO (978 mAhg-1) has been estimated to be superior to that of graphite (372 mAhg−1) [2]. High capacity anodes such as zinc based usually suffer severe capacity fading, stemming from both the quick aggregation of zinc particles and the huge volume expansion during Li+ insertion/extraction cycles, which cause pulverization of the anodes and electrical detachment of active materials [3]. MWCNT buckypaper substrate is considered as a buffer material to prevent mechanical disintegration of anode material during the battery applications. In this work, ZnO/MWCNT buckypaper nanocomposite films were prepared as free-standing anode materials by sol–gel spin coating method. To the best of our knowledge there is no work to be published by using highly porous MWCNT buckypapers to be infiltrated with ZnO sol by spin coating. It was aimed to accommodate the stresses arisen from the volume increase during charging process by using highly porous MWCNT network that coated with a thin layer of the ZnO. The structural properties and electrochemical performance of free standing ZnO/MWCNT buckypaper composite film anodes of CR2016 type Li-ion batteries were investigated. SEM (Scanning Electron microscopy), EDS (Energy-dispersive X-ray spectroscopy), XRD (X-ray diffraction) analyses and electrochemical performance tests were performed to characterize the nanocomposites. The cells were charged and discharged at 25 °C between fixed voltage limits (2.5 V to 0.2 V) on an MTI model of BST8-MA battery tester.

[1] Y. Wang, F. Su, J.Y. Lee, X.S. Zhao, Chem. Mater., 18, 1347-1353 (2006).

[2] M.O. Guler, T. Cetinkaya, U. Tocoglu, H. Akbulut, Microelectronic Engineering, doi:10.1016/j.mee.2013.12.029 (2014).

[3] X.H. Huang, X.H. Xia, Y.F. Yuan, F. Zhou, Electrochim. Acta, 56, 4960-4965 (2011).
Self-Discharge Phenomena in LiCoPO4 Electrodes
Authors: Brutti Sergio , Manzi Jessica , Vitucci Francesco , Trequattrini Francesco , Paolone Annalisa , Di Lecce Daniele , Panero Stefania
Published: February 2020

Polyanion-type materials, like lithium iron phosphate, are one of the recent great success in the research field of applied electrochemistry. Within this family, LiFePO4 (LFP) is a now mature material and its properties have been largely optimized thus opening the door to its commercial exploitation as cathode material in lithium-ion cells for power tools. In recent years the attention of the scientific community is focusing the great advantage of the substitution in the LFP lattice of Fe with Mn, Co or Ni. In fact the Mn3+/Mn2+, Co3+/Co2+ and Ni3+/Ni2+ couples show increasing redox potentials, all higher than the Fe3+/Fe2+, thus opening the door to large improvements in the energy performances. Among them LiCoPO4(LCP) is the best compromise: it shows in lithium cells an higher working potential compared to LFP, still within the working limits of the carbonate-based liquid electrolytes. However many fundamental aspects of the LCP properties and reaction mechanisms in lithium cells are not completely understood. Owing to this, large room for improvements in the performances in Li-cells of LCP is expected by assessing the synthesis route, the coatings, the doping/substitution and the electrolyte additives.

The aim of this communication is to present our recent results concerning the study of one of the most detrimental phenomenon observed in the use of LCP in lithium-ion cells: self-discharge.

Upon charge in lithium cells LCP undergoes to the following reversible two step oxidation:

LiCoPO4 → Li0.7CoPO4+0.3Li++0.3e- → CoPO4+ Li+ + e-

At the end of charge, in absence of flowing current, the self-relaxation of the charged LCP electrode is accompanied by a change in the OCV very similar to the discharge curve at constant current. Apparently prolonged OCV relaxation leads to the re-incorporation of lithium ions into the electrode that can be newly electrochemically charged. Self-discharge is a spontaneous phenomenon and has big technological consequences as it limits the use of LCP in commercial electrodes.

Here we discuss the results of our study of LCP self-discharged electrodes by ex-situ synchrotron powder diffraction, synchrotron infrared spectroscopy and transmission electron microscopy. Self-discharge apparently occurs by the following spontaneous reactions in OCV conditions:

CoPO4 + 0.7 Li++electrolyte (reduced form) → Li0.7CoPO4 + electrolyte (oxidized form)

Li0.7CoPO4 + 0.3 Li++electrolyte (reduced form) → LiCoPO4 + electrolyte (oxidized form)

The two self-discharge steps are accompained by accumulation of electrolyte decomposition by-products on the electrode surfaces.
Influence of Electrolyte Li+ Ion Concentration on the Growth of Li2O2 Discharge Products
Authors: Wang Deyu , Liu Yang
Published: February 2020

Organic Li-air battery is represented as the most promising energy-storage technology due to its ultra-high theoretical energy density.1,2 However, how to realize the advantage of high energy density has become one of the most important and urgent challenges. In our opinion, discharge process could be considered as fulfilling Li2O2 crystals in the pores of air cathode. Since supersaturation is the key driving force to influence the insoluble sedimentation process3, the growth of discharge products could be tailored by the activity of Li+ ions and/or reductive species. Therefore discharge products are possible to grow tri-dimensionally, instead of a thin layer, by adjusting Li+ ion concentration in the electrolytes.

In this work, it is investigated the influence of electrolyte Li+ ion concentrations on discharge behavior. As shown in Fig.1, the discharge behaviour could be divided into 3 regions as electrolyte concentration increases from 10-3 M to 5 M. The first region is ranged from 10-3 to 1 M, where discharge capacities are monotonic augmenting. It only delivers 2211 mAh gcarbon-1 at 10-3 M, and quickly ramps to 3013, 6055, and 7529 mAh gcarbon-1 at 10-2, 10-1 and 1 M separately. At 2 and 3 M, the discharge capacity hovers at an extremely high level, 12250 and 13245 mAh gcarbon-1 respectively. As the concentration further increases to 4 M and 5 M, the discharge capacity slumps severely to less than 4000 mAh gcarbon-1. The capacity variation is up to ~600% as a result of the tailoring effect of Li+ ion concentration in the electrolytes. The probable mechanism and further discussion will be presented in the conference.

Reference

1. P.G. Bruce.; S.A., Freunberger, L.J. Hardwick, J. M. Tarascon, Nature Mater. 2012, 11, 19;

2. G. Girishkumar, B. McCloskey, A.C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 2010, 1, 2193.

3. H.J. Scheel, T. Fukuda, Crystal Growth Technology John Wiley & Sons, Ltd. 2003.