Improving Performance of LiNi0.8Co0.1Mn0.1O2 Cathode Materials for Lithium-Ion Batteries by Doping with Molybdenum-Ions: Theoretical and Experimental Studies (original) (raw)
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ACS Energy Letters, 2019
Ni-rich materials of layered structure LiNi x Co y Mn z O 2, x > 0.5 are promising candidates as cathodes in high energy density Li-ion batteries for electric vehicles. The structural and cycling stability of Ni-rich cathodes can be remarkably improved by doping with small amount of extrinsic multivalent cations. In this study, we examine development of fast screening methodology for doping LiNi 0.8 Co 0.1 Mn 0.1 O 2 with cations Mg 2+ , Al 3+ , Si 4+ , Ti 4+ , Zr 4+ and Ta 5+ by a "top down" approach. The cathode material is coated by a precursor layer that contains the dopant, which then is introduced into the particles by diffusion during heat treatment at elevated temperatures. The methodology described herein can be applied to Ni-rich cathode materials and allows to identify relatively easily and promptly most promising dopants. Then further optimization work can lead to development of high capacity stable cathode materials. The present study marks Ta 5+ cations as very promising dopants for Ni-rich NCM cathodes.
Mo doping of layered Li (Ni x Mn y Co1-x -y -z M z )O2 cathode materials for lithium-ion batteries
International Journal of Energy Research, 2018
We systematically investigated the effects of Mo doping on the structure, morphology, and the electrochemical performance of Li (Ni x Mn y Co 1-x-y-z M z)O 2 (NMC) cathode materials for Li-ion batteries. Layered NMC cathodes were synthesized with the ratio of 111, 622, and 226 via spray pyrolysis yielding submicron-sized aggregates in the shape of hollow spherical particles. We performed X-ray diffraction analyses to determine the present phases and the ordering in structure. X-ray diffraction pattern of Mo-doped 111, 226, and 622 cathodes showed well-defined [006]/[102] and [108]/[110] doublets, indicating the layered structure, and good hexagonal ordering. Galvanostatic charge/discharge and electrical impedance spectroscopy measurements were carried out to reveal the effect of Mo doping on the electrochemical performance of the cathodes. Charge/discharge measurements after 20 cycles indicated that the Modoped 111 and 622 NMC cathodes performed a capacity retention of 80% and 81% respectively. Present findings reveal the stabilization effect of Mo in layered NMC structure, especially in the case of Ni-rich NMC cathodes.
Materials
In this work, we continued our systematic investigations on synthesis, structural studies, and electrochemical behavior of Ni-rich materials Li[NixCoyMnz]O2 (x + y + z = 1; x ≥ 0.8) for advanced lithium-ion batteries (LIBs). We focused, herein, on LiNi0.85Co0.10Mn0.05O2 (NCM85) and demonstrated that doping this material with high-charge cation Mo6+ (1 at. %, by a minor nickel substitution) results in substantially stable cycling performance, increased rate capability, lowering of the voltage hysteresis, and impedance in Li-cells with EC-EMC/LiPF6 solutions. Incorporation of Mo-dopant into the NCM85 structure was carried out by in-situ approach, upon the synthesis using ammonium molybdate as the precursor. From X-ray diffraction studies and based on our previous investigation of Mo-doped NCM523 and Ni-rich NCM811 materials, it was revealed that Mo6+ preferably substitutes Ni residing either in 3a or 3b sites. We correlated the improved behavior of the doped NCM85 electrode materials ...
mESC-IS 2019 : The Fourth International Symposium on Materials for Energy Storage and Conversion, 2019
This is the fourth activity in a series of symposia initiated back in 2015. The first symposium organized at METU comprised topics; solid state hydrogen storage, fuel cell-electrolysers and batteries-supercapacitors. This was followed by the second symposium in Cappadocia in Ortahisar 2017. The third symposium took place in Belgrade in September of 2018. In this series emphasis varied from one topic to the other. The current symposium comprises again three activity areas; namely, batteries-supercapacitors, fuel cells-electrolysers and hydrides for energy storage and conversion. The symposium, as before, has a fair balance of plenary sessions covering cross-cutting issues and the state of the art reviews and in-depth parallel sessions with contributed papers and poster presentation. Summer school is an integral part of this symposium. This has preceded the symposium and span over a four day period from September 7 th to 10 th , taken place at Mugla Sıtkı Koçman University. It comprised overviews on selected topics in energy storage and conversion with the view of acquainting the newcomers with the essentials of the topic plus portraying an outlook for possible future direction of research in the respective fields. Following recommendations made in mESC-School 2017 Cappadocia, we have introduced hands-on sessions into the program on selected techniques in material and electrochemical characterization. A substantial number of trainees from a variety of institutions in different disciplines, some new or early in their graduate study, some quite experienced have benefited greatly from this experience. This event was made possible with generous support of several institutions as well as of sponsors. We would like to acknowledge TUBITAK for the support both for summer school through the program 2237-A and symposium through 2223-B. ENDAM workshop was made possible by funds from Ministry of Development which we also gratefully acknowledge. We also acknowledge the support of our respective universities in a number of ways. Tayfur Öztürk. on behalf of mESC-IS2019 Organizing Committee mESC-IS 2019, 4th Int. Symposium on Materials for Energy Storage and Conversion Akyaka, Mugla Summer School on Materials for Energy Storage and Conversion,mESC-School 2019 took place from 7 th to 11 th September 2019. A total of 48 participants have taken part in the summer school. The program comprised material/electrochemical Characterization techniques;
Stabilized Behavior of LiNi0.85Co0.10Mn0.05O2 Cathode Materials Induced by Their Treatment with SO2
ACS Applied Energy Materials, 2020
We present in this paper a modification and stabilization approach for the surface of a high specific capacity Ni-rich cathode material LiNi 0.85 Co 0.10 Mn 0.05 O 2 (NCM85) via SO 2 gas treatment at 250-400 C, in order to enhance its electrochemical performance in advanced lithium-ion batteries. It was established that SO 2 interactions with NCM85 result in the formation of a nano-meter size Li 2 SO 4 surface layer on the oxide particles with no impact on the bulk structure of the material and its morphology. We consider the above interactions as oxidationreduction processes resulting in direct oxidation of sulfur and partial reduction of Ni 3+ as revealed by high-resolution XPS and electron paramagnetic resonance studies. The important impacts of the SO 2 treatment are remarkably stable cycling performance of cathodes comprising this material with ~10% increase in capacity retention and lesser voltage hysteresis upon cycling compared to untreated NCM85 cathodes. The SO 2-treated NCM85 material is also significantly thermally stable demonstrating lower heat evolution upon thermal reactions with standard EC-EMC/LiPF 6 solutions by 12-20%, compared to untreated material. The proposed approach to modify the surface of Ni-rich NCM cathode materials by SO 2 treatment is demonstrated to be a promising method to enhance their electrochemical performance. This work demonstrates a leap in performance of Ni-rich NCM cathode materials by increasing the content of nickel compared to any benchmark cathodes and a Promising approach for stabilization by surface modification.
Structural and Electrochemical Investigation of Li (Ni0. 4Co0. 15Al0. 05Mn0. 4) O2 Cathode Material
Li͑Ni 0.4 Co 0.15 Al 0.05 Mn 0.4 ͒O 2 was investigated to understand the effect of replacement of the cobalt by aluminum on the structural and electrochemical properties. In situ X-ray absorption spectroscopy ͑XAS͒ was performed, utilizing a novel in situ electrochemical cell, specifically designed for long-term X-ray experiments. The cell was cycled at a moderate rate through a typical Li-ion battery operating voltage range. ͑1.0-4.7 V͒ XAS measurements were performed at different states of charge ͑SOC͒ during cycling, at the Ni, Co, and the Mn edges, revealing details about the response of the cathode to Li insertion and extraction processes. The extended X-ray absorption fine structure ͑EXAFS͒ region of the spectra revealed the changes of bond distance and coordination number of Ni, Co, and Mn absorbers as a function of the SOC of the material. The oxidation states of the transition metals in the system are Ni 2+ , Co 3+ , and Mn 4+ in the as-made material ͑fully discharged͒, while during charging the Ni 2+ is oxidized to Ni 4+ through an intermediate stage of Ni 3+ , Co 3+ is oxidized toward Co 4+ , and Mn was found to be electrochemically inactive and remained as Mn 4+ . The EXAFS results during cycling show that the Ni-O changes the most, followed by Co-O, and Mn-O varies the least. These measurements on this cathode material confirmed that the material retains its symmetry and good structural short-range order leading to the superior cycling reported earlier.
Journal of Power Sources, 2012
First-principles calculations are used to analyze the phase stability, formation energy, and Li intercalation potential for a series of layered cathode materials. The calculations show LiNi 0.66 Co 0.17 Mn 0.17 O 2 as a promising cathode for lithium-ion batteries. The layer-structured LiNi 0.66 Co 0.17 Mn 0.17 O 2 is prepared via wet chemical route, followed by annealing at 1123 K and characterized using powder X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The characterization techniques reveal single-phase LiNi 0.66 Co 0.17 Mn 0.17 O 2 with highly ordered structure. Galvanostatic chargeedischarge curves recorded at 1C show the discharge capacity of ca. 167 mAh g À1 and good cyclic performance for 25 cycles.
ChemElectroChem, 2015
An integrated layered-spinel LiNi 0.33 Mn 0.54 Co 0.13 O 2 was synthesized by self-combustion reaction (SCR), characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. It was studied as a cathode material for Li-ion batteries and its electrochemical performance was compared with that of the layered cathode materialLiNi 0.33 Mn 0.33 Co 0.33 O 2 being operated at a wide potential window. The Rietveld analysis of LiNi 0.33 Mn 0.54 Co 0.13 O 2 indicated the presence of monoclinic Li[Li 1/3 Mn 2/3 ]O 2 (31%) and rhombohedral (LiNi x Mn y Co z O 2 ) (62 %) phases as the major components, and spinel (LiNi 0.5 Mn 1.5 O 4 ) (7 %) as a minor component, which is well supported by TEM and electron diffraction. A discharge specific capacity of about 170 mAh g -1 is obtained in the potential range of 2.3-4.9 V vs. Li at low rate (C/10) with excellent capacity retention upon cycling. On the other hand, LiNi 0.33 Mn 0.33 Co 0.33 O 2 (NMC111) synthesized by SCR exhibits an initial discharge capacity of about 208 mAh g -1 in the potential range of 2.3-4.9 V, which decreases to a value of 130 mAh g -1 after only 50 cycles. In turn, the multiphase structure of LiNi 0.33 Mn 0.54 Co 0.13 O 2 seems to stabilize the behavior of this cathode material even when polarized to high potentials. LiNi 0.33 Mn 0.54 Co 0.13 O 2 shows superior retention of average discharge voltage upon cycling as compared to that of LiNi 0.33 Mn 0.33 Co 0.33 O 2 when cycled in a wide potential range. Overall, ChemElectroChem 10.1002/celc.201500339 2 LiNi 0.33 Mn 0.54 Co 0.13 O 2 can be considered as a promising low cobalt content cathode material for Li ion batteries.
J. Phys. Chem. C , 2021
A cathode material containing Ni content over 80% suffers from a poor cycling performance, despite its promising performance in a lithium ion battery. By utilizing the first-principles calculation, we show that the stability and electrochemical performance of the NCM-89 material, LiNi0.89Co0.055Mn0.055O2, can be enhanced by doping with zirconium (+4) or molybdenum (+6). The present doping increases Ni2+s in the NCM-89 material and stabilizes the layer of transition metal by strengthening the Zr−O and Mo−O bonds. The doping also suppresses the phase transition from a layered-oxide to a spinel structure by restraining the migration of Ni2+ and thereby mitigating the release of an oxygen gas.