SnO2-coated LiCoO2 cathode material for high-voltage applications in lithium-ion batteries (original) (raw)
Improvement of electrochemical stability of LiCoO< sub> 2 cathode by a nano-crystalline coating
Journal of power sources, 2004
A nano-crystalline MgO coating was formed on the surface of LiCoO 2 particle via a sol-gel method. MgO coating can improve the cycling stability of LiCoO 2 significantly. After the 40th cycle a discharge capacity of more than 120 mAh/g was remained for 1 mol% MgO-coated LiCoO 2 , while only 13 mAh/g for pristine LiCoO 2 when both charged up to 4.7 V. During heat treatment and charge/discharge process, Mg 2+ in coatings will diffuse into LiO 2 -layers of LiCoO 2 , which does not cause any detectable shift in X-ray diffractometer (XRD) peak positions, but does impact the XRD peak intensity due to the aberrance of (0 0 3) plane. Mg 2+ ions existing in LiO 2 -layers will stabilize the lattice structure of LiCoO 2 , hence improve the cycling performance of LiCoO 2 cathode. More MgO coating on LiCoO 2 is detrimental to the electrochemical properties of LiCoO 2 cathode, probably due to the electrochemical inactivity of MgO particles.
Electrochimica Acta, 2018
Herein, the influence of the dopant concentration and the effect of varying the amount of the carbon coating for the electrochemical properties of Co-doped SnO 2 as lithium-ion anode material are presented. Pure SnO 2 and three different doping ratios of Co-doped SnO 2 (Sn 0.95 Co 0.05 O 2 , Sn 0.90 Co 0.10 O 2 , and Sn 0.85 Co 0.15 O 2) were synthesized and characterized regarding their structure, morphology, and electrochemical behavior. The results reveal that the Co content has a significant impact on the specific capacity and cycling stability, rendering Sn 0.90 Co 0.10 O 2 as the sample with the best electrochemical performance among these three dopant ratios. The impact of the carbon coating content was explored for two different concentrations, i.e., 16 wt% (Sn 0.90 Co 0.10 O 2-C16%) and 50 wt% (Sn 0.90 Co 0.10 O 2-C50%), reflecting that the carbon coating as such and concerning the eventual amount has a significant influence on the cycling stability, coulombic efficiency, and rate capability.
Journal of Power Sources, 2008
Lithium-ion battery a b s t r a c t LiCoO 2 particles were coated with various wt.% of lanthanum aluminum garnets (3LaAlO 3 :Al 2 O 3 ) by an in situ sol-gel process, followed by calcination at 1123 K for 12 h in air. X-ray diffraction (XRD) patterns confirmed the formation of a 3LaAlO 3 :Al 2 O 3 compound and the in situ sol-gel process synthesized 3LaAlO 3 :Al 2 O 3 -coated LiCoO 2 was a single-phase hexagonal ␣-NaFeO 2 -type structure of the core material without any modification. Scanning electron microscope (SEM) images revealed a modification of the surface of the cathode particles. Transmission electron microscope (TEM) images exposed that the surface of the core material was coated with a uniform compact layer of 3LaAlO 3 :Al 2 O 3 , which had an average thickness of 40 nm. Galvanostatic cycling studies demonstrated that the 1.0 wt.% 3LaAlO 3 :Al 2 O 3 -coated LiCoO 2 cathode showed excellent cycle stability of 182 cycles, which was much higher than the 38 cycles sustained by the pristine LiCoO 2 cathode material when it was charged at 4.4 V.
Journal of The Electrochemical Society, 2010
Ultrathin atomic layer deposition ͑ALD͒ coatings enhance the performance of lithium-ion batteries ͑LIBs͒. Previous studies have demonstrated that LiCoO 2 cathode powders coated with metal oxides with thicknesses of ϳ100 to 1000 Å grown using wet chemical techniques improved LIB performance. In this study, LiCoO 2 powders were coated with conformal Al 2 O 3 ALD films with thicknesses of only ϳ3 to 4 Å established using two ALD cycles. The coated LiCoO 2 powders exhibited a capacity retention of 89% after 120 charge-discharge cycles in the 3.3-4.5 V ͑vs Li/Li + ͒ range. In contrast, the bare LiCoO 2 powders displayed only a 45% capacity retention. Al 2 O 3 ALD films coated directly on the composite electrode also produced improved capacity retention. This dramatic improvement may result from the ultrathin Al 2 O 3 ALD film acting to minimize Co dissolution or reduce surface electrolyte reactions. Similar experiments with ultrathin ZnO ALD films did not display enhanced performance.
Electrochimica Acta, 2017
Careful modulation of surficial and interfacial properties of electrode materials is a critical factor for determining overall electrochemical characteristics. Recent studies have indicated that metal oxide nanocoating layer (such as titanium (IV) oxide (TiO 2)) on metal oxide anodes (such as tin (IV) oxide (SnO 2)) exhibited superior electrochemical properties, but fundamental research on the effect and role of TiO 2 layer thickness has been limited. Here we have successfully conducted in-depth study on how the thickness of TiO 2 overlayer on SnO 2 can have significant influence in the overall parameters of electrochemistry. It is revealed that TiO 2 overlayer with 12 nm shows good cycle retention (75.8%) even after 80 cycles and retains capacity of 438.3 mAh g À1 even at high current density (5000 mA g À1). Surprisingly, it was further discovered that TiO 2 layer not only alleviates the volume expansion but also helps to facilitate Li ion transport compared with SnO 2. The improvements in both ionic and electrical conductivity of TiO 2 layer are main factors in better cycle retention and rate capabilities. Finally, in situ transmission electron microscopy analysis was adopted to observe the growth dynamics of solid electrolyte interphase layer on TiO 2 @SnO 2 , which demonstrates that TiO 2 overlayer results in homogeneous and thinner interphase layer compared with SnO 2 NTs.
Binder free porous ultrafine/nano structured LiCoO 2 cathode from plasma deposited cobalt
Electrochimica Acta, 2011
Increasing global demand for rechargeable lithium (Li) ion batteries has been driving the research on innovative processing techniques and material systems for cheaper production of battery electrodes. While cost reduction is important, obtaining desired microstructures in the active electrode material is also very critical for efficient performance of the batteries. Conventional processing of bulk scale Liion battery electrodes involves time consuming and multi-step processes starting from the production of active powder materials, blending with conductive additives and binders to develop the electrode material coating on a current collector. On the other hand, thin film battery technologies employ expensive vapor based or sputtering or laser ablation techniques to develop the electrodes. In this study, an innovative, rapid and a two step scalable manufacturing process has been developed. While capable of developing porous and ultrafine/nano structured oxide based LiCoO 2 cathode material directly on a charge collector from metallic Cobalt (Co) coatings, the process does not require polymeric binders. Following this approach, LiCoO 2 cathodes were synthesized directly on a stainless steel charge collector from plasma sprayed Co coatings via thermal treatments using aqueous LiNO 3 solution. X-ray diffraction (XRD) studies confirmed presence of LiCoO 2 hexagonal phase. Microstructural and phase analysis showed porous active material with ultrafine/nano structural features along with imperfections (e.g., dislocations). Electrochemical characterization illustrated an average voltage around 3.9 V with a specific discharge capacity around 70-85% of the nominal capacity (∼138 mAh/g) against Li counter electrode. However, process optimization in terms of plasma spray coatings and thermal treatments, and addition of carbon may enhance the performance of LiCoO 2 electrodes. Absence of polymeric binders makes these electrodes suitable for high temperature battery applications.
Jurnal Kejuruteraan, 2018
The development of suitable electrode materials for lithium ion batteries (LIBs) to enhance the performance of LIBs in order to meet increasingly demand globally is one of the challenges. Thus, for almost three decades since 1980, continuous study for high performance LIBs electrode has been done. In this report, the optimization charge-discharge characteristic of LiNiCoMnO 2 (LNCM) cathode-layered structured material with lithium metal as anode has been evaluated. The electrode was assembled together with Celgard as separator and organic electrolyte Lithium hexafluorophosphate (1M LiPF 6 , EC:DEC 1:1) in coin cells (CR2032) under argon atmosphere inside a glove box. The charge-discharge performance test was conducted using Neware battery testing system. The discussion in this paper is focusing on the characteristic features of the chargedischarge profile, optimize charge-end voltage and rate capability (C-rate). The studies discovered the voltage range has been optimized up to 3.3-4.5 V at a constant current of 0.35 mA (0.1 C) with voltage plateau of 4.0 V. The result indicated the optimized range has the highest specific capacity of 118 mAh/g and most stable coulombic efficiency (94.3%).
Cathode Materials for Lithium-ion Batteries: A Brief Review
Journal of New Materials for Electrochemical Systems, 2021
Layered lithium cobalt oxide (LiCoO 2 ) as a pioneer commercial cathode for lithium-ion batteries (LIBs) is unsuitable for the next generation of LIBs, which require high energy density, good rate performance, improved safety, low cost, and environmental friendliness. LiCoO 2 suffers from structural instability at a high level of delithiation and performance degradation when overcharged. Besides, cobalt, a significant constituent of LiCoO 2 is more costly and less environmentally friendly than other transition metals. Therefore, alternative cathode materials are being explored to replace LiCoO 2 as cathode materials for high-performance LIBs. These new cathode materials, including lithiated transition metal oxides, vanadium pentoxides, and polyanion-type materials, are reviewed in this study. The various challenges hampering the full integration of these cathode materials in commercial LIBs and viable solutions are emphasised.
Coating technique for improvement of the cycling stability of LiCo/NiO< sub> 2 electrode materials
2006
We provide data on the changes in structure and composition of commercial LiNi 0.8 Co 0.2 O 2 electrode materials for lithium-ion batteries occurring after surface coating with two types of metal oxides: electrochemically active LiCoO 2 and inactive MgO. XRD analysis, SEM images, IR spectroscopy and EPR of low-spin Ni 3+ ions were carried out for structural characterisation of coated LiNi 0.8 Co 0.2 O 2 electrodes. Surface modification with LiCoO 2 was found to be a more effective route for improving the cycling stability of LiNi 0.8 Co 0.2 O 2. The favourable effect of LiCoO 2-coating was connected with an enhanced stability of the bulk composition and reduction of electrode/electrolyte interaction.