Pavia Spectroscopy Solution Manual Pdf
Victoria Steigerwald
We investigated high rate performance of all solid state lithium secondary batteries using LiCoO2 and LiNi0.8Co0.15Al0.05O2 coated with Li4Ti5O12 as active materials and the Li2S-P2S5 glass ceramic as a solid electrolyte. Sulfide based solid electrolyte (Li2S-P2S5 glass ceramic) were prepared by mechanical milling technique. The Li2S-P2S5 glass ceramic showed ionic conductivity as high as 4.010-3 S cm-1 at room temperature. The glass ceramics were highly stable against electrochemical window of 10V. Coated LiCoO2 and LiNi0.8Co0.15Al0.05O2 materials reduced an interfacial resistance between an electrode and a solid electrolyte. The high rate capability of the batteries using coated LiCoO2 and LiNi0.8Co0.15Al0.05O2 and the Li2S-P2S5 glass ceramic enhanced because of the decrease of the interfacial resistance of the batteries. The batteries using coated LiCoO2 and LiNi0.8Co0.15Al0.05O2 as an electrode and the glass ceramic as electrolyte showed a large discharge capacity of 110mAh g-1 at current density of 10mA cm-2 at room temperature. The batteries worked at high current density of 40mA cm-2 at a high temperature of 100C. The cycle performance of the batteries using coated an electrode at high temperature of 100C were highly stable without resistance increase after 15 cycles at the current density of 0.5mA cm-2. These results indicated providing good prospects for practical application of lithium secondary batteries free from safety issues.
All-solid-state lithium rechargeable batteries using inorganic solid electrolytes are recognized as an ultimate battery with high safety and reliability. We have developed sulfide glass-based electrolytes and found that the Li2S-P2S5 glass-ceramics exhibited high conductivity of over 10-3 S cm-1 at room temperature and wide electrochemical window. All-solid-state batteries Li-In/LiCoO2 using the Li2S-P2S5 glass-ceramic electrolytes showed excellent cyclability for 700 cycles at a limited current density. Surface coating LiCoO2 with an oxide buffer layer such as LiNbO3 and Li2SiO3 was reported to improve rate performance of all-solid-state batteries. The structure and morphology of the electrode/electrolyte interface affects the electrochemical performance of all-solid-state batteries. In this study, the solid-solid interface between LiCoO2 electrode and Li2S-P2S5 electrolyte was analyzed by TEM observation. An interfacial layer was detected by TEM at the LiCoO2/Li2S-P2S5 interface after the initial charge process. Furthermore, mutual diffusions of Co, P, and S at the interface between LiCoO2 and Li2S-P2S5 were observed. The mutual diffusion and the formation of the interfacial layer were suppressed using LiCoO2 particles coated with Li2SiO3 thin film. Interfacial structure and battery performance for several active materials including LiCoO2 will be discussed.
Anna Potapova 1 , Andrey Novoselov 1 , Alexander Mosunov 2 , Galina Zimina 1
1 Department of Chemistry and Chemical Engineering for Rare and Dispersed Elements, Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow Russian Federation, 2 Department of Chemistry, Lomonosov Moscow State University, Moscow Russian Federation
Bruce Dunn 1 , Jane Chang 2 , C. Kim 3 , Sarah Tolbert 4
1 Materials Science and Engineering, University of California at Los Angeles, Los Angeles, California, United States, 2 Chemical and Biomolecular Engineering, University of California at Los Angeles, Los Angeles, California, United States, 3 Mechanical and Aerospace Engineering, University of California at Los Angeles, Los Angeles, California, United States, 4 Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California, United States
Three-dimensional battery architectures offer a new approach for miniaturized power sources. The defining characteristic of 3-D battery designs is that transport between electrodes remains one-dimensional (or nearly so) at the microscopic level, while the electrodes are configured in non-planar geometries. Such configurations offer certain advantages, with one of the most attractive being the prospect of achieving high energy and power density within a small footprint area. These features are particularly important for integrated microsystems where the available area for the power source is limited to millimeter dimensions.The present paper reviews recent advances in the development of 3-D microbatteries which incorporate periodic electrode arrays. The design rules for such 3-D battery architectures have been established and methods for fabricating electrode arrays have been developed for a variety of materials. Our electrode array fabrication method for 3-D lithium-ion systems involves the combination of silicon micromachining with colloidal processing of electrode powders. Another key element in our 3-D battery designs is the use of a conformal electrolyte coating. Our progress in these areas will be reviewed along with a discussion of both the advantages offered by 3-D architectures and the challenges facing this technology.
Silicon and sulfur have among the highest theoretical specific capacities as anode and cathode materials, respectively, in Li-ion batteries. However, the use of these materials has been prevented in commercial Li-ion batteries due to a variety of problems, including structural changes and volume expansion during reaction. In addition, most studies on sulfur-based lithium batteries utilize metallic lithium as the anode, which is not practical due to safety issues relating to dendrite formation at the lithium surface. We report a novel lithium-ion battery consisting of a Li2S/mesoporous carbon composite cathode and a silicon nanowire anode that overcomes many of these issues. This new battery yields an ultrahigh theoretical specific energy of 1550 Wh kg-1, which is four times that of the theoretical specific energy of existing lithium-ion batteries based on LiCoO2 cathodes and graphite anodes. The nanostructured design of the Li2S/mesoporous carbon composite cathode serves to improve electronic conductivity and to limit lithium polysulfide dissolution into the electrolyte, which results in good performance compared to previous research on Li2S electrodes. On the anode side, the silicon nanowire architecture allows for the requisite volume expansion during alloy formation without pulverization; silicon nanowires have been shown to significantly improve capacity retention with cycling. By combining these electrodes in full battery cells, we have experimentally realized a high initial specific energy of 630 Wh kg-1 based on the mass of the active electrode materials. Our Li2S/Si battery concept, which does not incorporate unsafe lithium metal, offers significant safety advantages over the Li/S battery and could have a large impact on applications such as vehicle electrification and portable electronics.
Chunmei Ban 1 , Dane Gillaspie 1 , Zhuangchun Wu 1 , YoonSeok Jung 1 , Anne Dillon 1
1 Chemical and Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado, United States
Due to increasing demand for the development of rechargeable Li-ion batteries for the transportation sector, safety and thermal stability of electrode materials currently constitute a significant research effort. Inferior electrochemical performance and unstable side reactions of electrode materials often result from surface reactions including: electrolyte decomposition, the formation of a solid-state interface, and cation-dissolution from electrode materials. Side reactions on nanoscale materials are, of course, more severe because of increased surface area. Therefore, chemical modification of electrode surfaces is currently being extensively studied. Furthermore, sustainable and safe cycling has been demonstrated by depositing thin surface coatings of inert materials such as Al2O3 or ZrO2 as well as conductive materials including carbon. However, there has been limited research on surface treatments of ionic conducting materials such as LiAlF4, beta-alumina etc. The goal of this work is to understand how an ionic conducting coating may protect electrode materials in order to improve Li-ion battery performance. Thermal evaporation, pulsed laser deposition as well as atomic layer deposition may be employed to coat various Li-ion battery electrodes. The effect of ionic-conductive coatings to improve electrochemical performance will be discussed in detail here.
Three dimensional (3-D) thin-film battery structures are very attractive because they have higher energy storage per footprint area than current 2-D thin-film battery structures [1]. Trench structures on a silicon wafer are one candidate of 3-D structures that can be simply fabricated by a microelectronics process [2]. Bates et al. indicated that LiCoO2 films synthesized on a planar substrate facing the source are grown to preferential (101) and (104) crystal orientations [3]. The film texture and microstructure enables rechargeable thin-film lithium batteries to provide a high-rate cycling behavior. LiCoO2 vapor synthesis on a trench structure, however, may provide quite different film properties that impact the battery performance. This research reports LiCoO2 film depositional properties on a trench structure by a RF-magnetron sputtering approach. Using a Direct Simulation Monte Carlo (DSMC) simulation, we will explore sputtering natures of LiCoO2 film properties on a trench structure.References[1] Jeffrey W. Long, Bruce Dunn, Debra R. Rolison and Henry S. White, Chem. Rev. 104 (2004) 4463-4492.[2] Loic Baggetto, Rogier A. H. Niessen, Fred Roozeboom and Peter H. L. Notten, Adv. Funct. Mater. 18 (2008)1057-1066.[3] J. B. Bates, N. J. Dudneys, B. J. Neudecker, F. X. Hart, H. P. Jun and S. A. Hackney, J. Electrochem. Soc. 147 (2000) 59-70.Acknowledgement: Research sponsored by the Division of Materials Sciences and Engineering, U.S. Department of Energy
Lithium-ion batteries have become the primary energy choice for low power applications, and are now being sought after for high power applications in hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and electric vehicles (EV). To be successful in the high-power market, the short comings that have confined the use of conventional Li-ion batteries to low-power applications need to be addressed. We are in the process of fabricating an all solid-state Li-ion battery that mitigates the safety issues inherent in conventional Li-ion batteries. This is accomplished by using a non-carbon based anode material, Cu2Sb, that lithiates sufficiently above the potential for metallic lithium dendrite growth; thereby mitigating the potential for fire. We have successfully fabricated thin film half and full cells using electrodeposited Cu2Sb as the anode material, an electrochemically grown electrolyte, and various cathode materials. Preliminary cycling performance of these solid-state thin film batteries will be presented to demonstrate the usefulness of the fabrication process. Unfortunately, solid-state diffusion limits the deliverable power of a solid-state battery and is thus the most important performance characteristic that must be overcome in order for solid-state Li-ion batteries to be used in electric powered vehicles. We are designing a high surface area, three dimensional (3D) solid-state battery based on an array of Cu2Sb nanowires with average diameters of 40 nm. The nanowires are coated with a solid electrolyte, and the void space between the wires is filled with nanoparticles of cathode material. A battery based on this 3D nanoscale morphology will benefit from a shorter diffusion distance for the lithium ions and a three orders of magnitude increase in the active materials specific surface area. These two properties are predicted to provide higher power output then conventional non-solid state Li-ion batteries. The third short coming of traditional Li-ion batteries for use in electric powered vehicles is cost. For this reason, the fabrication process of the 3D nanowire battery is based on (1) electrodeposition of the Cu2Sb from aqueous solution, (2) electrochemical formation of the electrolyte onto these wires, and (3) dip casting the cathode nanoparticles between the Cu2Sb nanowires. None of these processes require high vacuum, high temperature processes or expensive equipment, thereby reducing the overall cost of the battery fabrication in comparison to traditional manufacturing costs. The issues that are currently being addressed in the fabrication process of an all solid-state 3D battery based on nanowires arrays of Cu2Sb will be discussed, along with some preliminary results of the first generation prototype.
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