A Novel Coating Technology for Preparation of Cathodes in Li-Ion Batteries (original) (raw)
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The role of carbon black distribution in cathodes for Li ion batteries
Journal of Power Sources, 2003
The influence of carbon black distribution/arrangement in cathode composite on cathode performance is studied using three types of active materials: LiMn 2 O 2 -spinel, LiCoO 2 , and LiFePO 4 . To the active materials, carbon black is added in two different ways: (a) using a conventional mixing procedure and (b) using a novel coating technology (NCT) invented in our laboratory. Different technologies yield different arrangement (distribution) of carbon black around active particles. It is shown that the uniformity of carbon black distribution affects significantly the cathode kinetics, regardless of the type of active particles used. A simple model explaining the influence of carbon black distribution on cathode kinetics is presented. #
Optimization of Cathode Material Components by Means of Experimental Design for Li-Ion Batteries
Journal of Electronic Materials, 2020
Table I. Review on studies on electrode preparation and cathode type Author Description Cathode Material References Dominko Uniform distribution of carbon black LCO, LFP, LMO Refs. 18-20 Zheng Cooperation between active material, binder and conductive carbon NCA Ref. 17 Chia-Chen Li Distribution of binder (water-based SBR/SCMC and organic-based PVDF) LCO Ref. 21 Bauer High shear Dry mixing Distribution of carbon black Additional graphite or carbon black and calendering Not mentioned Ref. 22 Fransson Carbon black and binder Not mentioned Ref. 27 Cao Surface modified graphite Not mentioned Ref. 28 Guy Binder PEO/CB ratio Li 2 V 3 O 8 Ref. 23 Li Carbon conductive additive with different dimensions (MWCNT, CB, graphite) LFP Ref. 29 Bockholt Processing Additive selection + slurry preparation + calendering NCM Ref. 24 Zhang Carbon nanomaterial Carbon black, super P, acetylene black, carbon nanofiber, carbon nanotubes Not Mentioned Ref. 25 Spahr Comparing carbon black (C45,C65) and graphite (KS6, KS6L,SFG6L) LCO Ref. 26 Optimization of Cathode Material Components by Means of Experimental Design for Li-Ion Batteries
Surface Characterization of Electrodes from High Power Lithium-Ion Batteries
Journal of The Electrochemical Society, 2002
X-ray photoelectron spectroscopy and scanning electron microscopy were used to study electrode samples obtained from 18650type lithium-ion cells subjected to accelerated calendar-life testing at temperatures ranging from 25 to 70°C and at states-of-charge from 40 to 80%. The cells contained LiNi 0.8 Co 0.2 O 2 -based positive electrodes ͑cathodes͒, graphite-based negative electrodes ͑anodes͒, and a 1 M LiPF 6 ethylene carbonate:diethyl carbonate ͑1:1͒ electrolyte. The results from electrochemically treated samples showed surface film formation on both electrodes. The positive electrode laminate surfaces contained a mixture of organic species that included polycarbonates, and LiF, Li x PF y -type and Li x PF y O z -type compounds. The same surface compounds were observed regardless of test temperature, test duration, and state-of-charge. On the negative electrode laminates lithium alkyl carbonates (ROCO 2 Li) and Li 2 CO 3 were found in addition to the above-mentioned compounds. Decomposition of lithium alkyl carbonates to Li 2 CO 3 occurred on negative electrodes stored at elevated temperature. Initial depth-profiling results suggest that the surface layer thickness is greater on positive electrode samples from cells stored at high temperature than on samples from cells stored at room temperature. This observation is significant because positive electrode impedance, and more specifically, chargetransfer resistance at the electrode/electrolyte interface, has been shown to be the main contributor to impedance rise in these cells.
A simple mechano-thermal coating process for improved lithium battery cathode materials
Journal of Power Sources, 2004
A simple, economical and convenient mechano-thermal coating procedure for the production of LiCoO 2 with improved cycling performance is described. The coating material was pre-formed nanoparticulate fumed silica. TEM studies with a 1.0 wt.% silica-coated cathode suggested that the silica species partially diffused into the bulk of the cathode material. XRD studies showed a diminished lattice parameter c upon coating, indicating that a substitutional compound of the LiSi y Co 1−y O 2+0.5y type might have formed upon calcination. SEM images, R-factor values from XRD studies and electrochemical studies showed that a coating level of 1.0 wt.% gave an optimal performance in capacity and cyclability. SEM images showed that above this level, the excess silica formed spherules, which got glued to the coated cathode particles. Galvanostatic cycling studies showed that at a coating level of 1.0 wt.%, cyclability improved three and nine times for two commercial LiCoO 2 samples.
A short review on electrode materials and processing of Lithium-ion battery
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The purpose of this paper is to review the efficient electrode materials and process adopted for electrode fabrication (mainly cathode) of Lithium-ion Batteries (LIBs). This article discusses the high performance cost effective active materials for fabrication of cathode. The comparison and difficulties of both the processing methods using non-aqueous and aqueous medium has been discussed in terms of cost and environmental issue. In this article various aqueous formulations of cathode electrode slurry and their electrical properties as well as the electrochemical performance of LIBs are reported with the application of various water soluble binder and other additives.
A short review on surface chemical aspects of Li batteries: A key for a good performance
Journal of Power Sources, 2009
We review herein several important aspects of surface chemistry in Li-ion batteries, and discuss the use of ionic liquids (ILs) for rechargeable Li batteries. We explored the suitability of ILs for 5 V cathodes and Li-graphite anodes. Some advantages of the use of ILs to attenuate the thermal behavior of delithiated cathode materials are demonstrated. We also report briefly on a comparative study of the following cathode materials: LiNi 0.5 Mn 0.5 O 2 ; LiNi 0.33 Mn 0.33 Co 0.33 O 2 ; LiNi 0.4 Mn 0.4 Co 0.2 O 2 ; LiNi 0.8 Co 0.15 Al 0.05 O 2 and LiMnPO 4 , in standard electrolyte solutions based on mixtures of alkyl carbonates and LiPF 6 . We also discuss aging, rate capability, cycle life and surface chemistry of these cathode materials. The techniques applied included electrochemical measurements, e.g., XRD, HRTEM, Raman spectroscopy, XPS and FTIR spectroscopy. We found that ILs based on cyclic quaternary alkyl ammonium cations may provide much better electrolyte solutions for 5 V cathodes than standard electrolyte solutions, while being quite suitable for Li-graphite electrodes. All the lithiated transition metal oxides studied (as mentioned above) develop unique surface chemistry during aging and cycling due to the acid-base and nucleophilic reactions of their surface oxygen anions. LiMn 0.33 Ni 0.33 Co 0.33 O 2 has the highest rate capability compared to all the other abovementioned cathode materials. Cathodes comprising nanometric size carbon-coated LiMnPO 4 produced by HPL demonstrate a better rate capability than LiNi 0.5 Mn 0.5 O 2 and LiNi 0.8 Co 0.15 Al 0.05 O 2 cathodes. The former material seems to be the least surface reactive with alkyl carbonates/LiPF 6 solutions, among all the cathode materials explored herein.
Electrochimica Acta, 2013
In this study, highly dispersive spherical Li-rich solid solution (Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 ) particles are successfully synthesized by a co-precipitation method. Then these particles are treated with aluminum nitrates ethanol solution at 80 • C. The treatment can extract lithium (Li 2 O) from the Li 2 MnO 3 component in the composite of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 . Simultaneously, a thin layer of Al 2 O 3 can be precipitated on the surface of the electrode particles via direct thermal decomposition of aluminum nitrates. After treatment, the first-cycle coulombic efficiency of the electrode increases from 72.1% to 93.6%, meanwhile it shows a superior cycling stability at 100 mA g −1 with a discharge capacity of around 220 mAh g −1 and retention of 92.5% after 100 cycles, which is much higher than that of the pristine electrode (83.2%). Even at a high current density of 2 A g −1 (10 C), the discharge capacity could still achieve and well maintain as high as 140 mAh g −1 .
Investigation of new types of lithium-ion battery materials
Journal of Power Sources, 2002
This paper reports part of the activities in progress in our laboratory in the investigation of electrode and electrolyte materials which may be of interest for the development of lithium-ion batteries with improved characteristics and performances. This investigation has been directed to both anode and cathode materials, with particular attention to convertible oxides and defect spinel-framework Li-insertion compounds in the anode area and layered mixed lithium±nickel±cobalt oxide and high voltage, metal type oxides in the cathode area. As for the electrolyte materials, we have concentrated the efforts on composite polymer electrolytes and gel-type membranes. In this work we report the physical, chemical and electrochemical properties of the defect spinel-framework Li-insertion anodes and of the high voltage, mixed metal type oxide cathodes, by describing their electrochemical properties in cells using either``standard'' liquid electrolytes and`a dvanced'' gel-type, polymer electrolytes.
Bashkir chemistry journal, 2018
Èçó÷åíî âëèÿíèå ïðèðîäû ñâÿçóþùåãî ïîëèìåðà óãëåðîä-ïîëèìåðíûõ ïîêðûòèé äëÿ òîêîâûõ êîëëåêòîðîâ ïîëîaeèòåëüíûõ ýëåêòðîäîâ íà èõ àäãåçèþ, ýëàñòè÷íîñòü, óäåëüíîå îáúåìíîå ñîïðîòèâëåíèå, íàáóõàåìîñòü â ýëåêòðîëèòàõ äëÿ ëèòèéèîííûõ è ëèòèé-ñåðíûõ àêêóìóëÿòîðîâ. Íàèáîëåå ïåðñïåêòèâíûìè ïîëèìåðíûìè ñâÿçóþùèìè ïîêðûòèé òîêîâûõ êîëëåêòîðîâ ëèòèé-ñåðíûõ àêêóìóëÿòîðîâ ÿâëÿþòñÿ àêðèëîâàÿ ñìîëà, íàòóðàëüíûé è õëîðîïðåíîâûé êàó÷óê, à äëÿ ëèòèéèîííûõ àêêóìóëÿòîðîâ-ïîëèîðãàíîñèëîêñàíîâàÿ ñìîëà, ïîëèóðåòàí è ïîëèâèíèëèäåíôòîðèä. Êëþ÷åâûå ñëîâà: àäãåçèÿ; ëèòèåâûå àêêóìóëÿòîðû; ëèòèé-èîííûå àêêóìóëÿòîðû; ëèòèéñåðíûå àêêóìóëÿòîðû; íàáóõàåìîñòü; ïîëîaeèòåëüíûé ýëåêòðîä; ñîïðîòèâëåíèå; òîêîâûé êîëëåêòîð; òîêîïðîâîäÿùèå çàùèòíûå ïîêðûòèÿ; ýëàñòè÷íîñòü. Effect of nature of binding polymer of carbonpolymer coatings on current collectors for positive electrodes of lithium batteries on their adhesion, flexibility, specific resistance, swelling in electrolytes for lithium-ion batteries and lithiumsulfur batteries was studied. The most promising polymer binder for coatings of the current collectors for lithium-sulfur batteries are poly (acrylic acid), nature and chloroprene rubbers, and for lithium-ion batteries are polyorganosiloxane resin, polyurethane and polyvinylidene fluoride.