scholarly journals Tungsten Infused Grain Boundaries Enabling Universal Performance Enhancement of Co-Free Ni-Rich Cathode Materials

2021 ◽  
Author(s):  
Divya Rathore ◽  
Chenxi Geng ◽  
Nafiseh Zaker ◽  
Ines Hamam ◽  
Yulong Liu ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Cathode Materials ◽  
Performance Enhancement ◽  
Theoretical Modelling ◽  
Layered Oxides ◽  
Particle Structure ◽  
Capacity Retention ◽  
Primary Particles ◽  
Interfacial Reactivity ◽  
Reduced Surface

Abstract Ni-rich cathode materials suffer from poor capacity retention due to micro-cracking and interfacial reactivity with electrolyte. Addition of tungsten (W) to some Ni-rich materials can improve capacity retention. Here, a WO3 surface coating is applied on Ni-rich hydroxide precursors before heating with lithium hydroxide. After heating in oxygen, Ni-rich materials with any of the commonly used dopants (magnesium, aluminum, manganese, etc.) show a “universal” improvement in capacity retention. Experimental characterization and theoretical modelling showed W was concentrated in the grain boundaries between the primary particles of secondary particles of the layered oxides, and W is incorporated in amorphous LixWyOz phases rather than as a substituent in the LiNiO2 lattice. This self-infusion of W in the grain boundaries during synthesis also significantly restricts primary crystallite grain growth. Along with smaller primary grain size, the LixWyOz phases in the grain boundaries lead to improved resistance to microcracking and reduced surface or interfacial reactivity. Improving the intrinsic properties of primary grains through doping of Mg, Al or Mn and reinforcing the secondary particle structure mechanically and chemically using W or a similar element, M, that forms LixMOy phases and does not substitute into LiNiO2 is a universal strategy to improve polycrystalline Ni-rich materials.

Boosting Cycling Stability of Ni-rich Layered Oxide Cathode by Dry Coating of Ultrastable Li3V2(PO4)3 Nanoparticles

Nanoscale ◽  
2021 ◽  
Author(s):  
Dongdong Wang ◽  
Qizhang Yan ◽  
Mingqian Li ◽  
Hongpeng Gao ◽  
Jianhua Tian ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Cathode Materials ◽  
Lithium Ion ◽  
High Energy ◽  
Cycling Stability ◽  
Next Generation ◽  
Layered Oxides ◽  
Dry Coating ◽  
Layered Oxide ◽  
Oxide Cathode

Nickel (Ni)-rich layered oxides such as LiNi0.6Co0.2Mn0.2O2 (NCM622) represent one of the most promising candidates for the next-generation high-energy lithium-ion batteries (LIBs). However, the pristine Ni-rich cathode materials usually suffer...

Overlithiation of LiNi0.8Co0.2O2 for Increased Performance in Li-Ion Batteries

2014 ◽  
Vol 938 ◽  
pp. 253-256
Author(s):  
Hashlina Rusdi ◽  
Norlida Kamarulzaman ◽  
Rusdi Roshidah ◽  
Kelimah Elong ◽  
Abd Rahman Azilah
Keyword(s):  
Cathode Materials ◽  
Structural Instability ◽  
Cation Ordering ◽  
Capacity Fading ◽  
Capacity Retention ◽  
Battery Capacity ◽  
Li Ion ◽  
Battery Application ◽  
Charge Discharge ◽  
Better Than

Layered LiNi1-xCoxO2 is one of the promising cathode materials for Li-ion battery application. However, the Ni rich cathode materials exhibit low capacity and bad capacity retention. This is due to factors such as disorder and structural instability when Li is removed during charge-discharge. Overlithiation of cathode materials is expected to improve the cation ordering and structural stability. Good cation ordering will increase the battery capacity. During charge-discharge, the irreversible Li+ loss can be replaced to a certain extent by the interstitial Li+ ions in the lattice of the LixNi0.8Co0.2O2 material. This helps reduce capacity fading of the cathode materials. In this work the overlithiation of LiNi0.8Co0.2O2 is done by interstitially doping Li+ in the LiNi0.8Co0.2O2 materials producing Li1.05Ni0.8Co0.2O2 and Li1.1Ni0.8Co0.2O2. Results showthat the performance of the overlithiated LiNi0.8Co0.2O2 materials is better than pure LiNi0.8Co0.2O2.

Tailoring atomic distribution in micron-sized and spherical Li-rich layered oxides as cathode materials for advanced lithium-ion batteries

2016 ◽  
Vol 4 (20) ◽  
pp. 7689-7699 ◽  
Author(s):  
Peiyu Hou ◽  
Guoran Li ◽  
Xueping Gao
Keyword(s):  
Thermal Stability ◽  
Energy Density ◽  
Lithium Ion Batteries ◽  
Cathode Materials ◽  
Concentration Gradient ◽  
Lithium Ion ◽  
Cycle Life ◽  
Layered Oxides ◽  
Long Cycle ◽  
Long Cycle Life

A concentration-gradient doping strategy is introduced into micron-sized spherical Li-rich layered oxides. As a result, they exhibit high volumetric energy density, long cycle life and enhanced thermal stability.

scholarly journals Modelling Cationic Diffusion in Nickel-Based Honeycomb Layered Tellurates using Vashishta-Rahman Interatomic Potential and Relevant Insights

2021 ◽  
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Godwill Mbiti Kanyolo ◽  
Titus Masese
Keyword(s):  
Performance Enhancement ◽  
Interatomic Potential ◽  
Theoretical Studies ◽  
Layered Oxides ◽  
Ionic Radii ◽  
Diffusion Channel ◽  
Exponential Increase ◽  
Potential Parameters ◽  
Insight Into

<b>Although the fascinatingly rich crystal chemistry of honeycomb layered oxides has been accredited as the propelling force behind their remarkable electrochemistry, the atomistic mechanisms surrounding their operations remain unexplored. Thus, herein, we present an extensive molecular dynamics study performed systematically using a refined set of inter-atomic potential parameters of <i>A</i><sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub> (where <i>A</i> = Li, Na, and K). We demonstrate the effectiveness of the Vashishta-Rahman form of the interatomic potential in reproducing various structural and transport properties of this promising class of materials and predict an exponential increase in cationic diffusion with larger interlayer distances. The simulations further demonstrate the correlation between broadened inter-layer (inter-slab) distances associated with the larger ionic radii of K and Na compared to Li and the enhanced cationic conduction exhibited in K<sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub> and Na<sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub> relative to Li<sub>2</sub>Ni<sub>2</sub>TeO<sub>6</sub>. Whence, our findings connect lower potential energy barriers, favourable cationic paths and wider bottleneck size along the cationic diffusion channel within frameworks (comprised of larger mobile cations) to the improved cationic diffusion experimentally observed in honeycomb layered oxides. Furthermore, we explicitly study the role of inter-layer distance and cationic size in cationic diffusion. Our theoretical studies reveal the dominance of inter-layer distance over cationic size, a crucial insight into the further performance enhancement of honeycomb layered oxides.</b><br>

scholarly journals Modelling Cationic Diffusion in Nickel-Based Honeycomb Layered Tellurates using Vashishta-Rahman Interatomic Potential and Relevant Insights

2021 ◽  
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Godwill Mbiti Kanyolo ◽  
Titus Masese
Keyword(s):  
Performance Enhancement ◽  
Interatomic Potential ◽  
Layered Oxides ◽  
Ionic Radii ◽  
Diffusion Channel ◽  
Atomic Potential ◽  
Exponential Increase ◽  
Potential Parameters ◽  
Insight Into

<b>Although the fascinatingly rich crystal chemistry of honeycomb layered oxides has been accredited as the propelling force behind their remarkable electrochemistry, the atomistic mechanisms surrounding their operations remain unexplored. Thus, herein, we present an extensive molecular dynamics study performed systematically using a reliable set of inter-atomic potential parameters of </b><i>A</i><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b> (where </b><i>A</i><b> = Li, Na, and K). We demonstrate the effectiveness of the Vashishta-Rahman form of the inter-atomic potential in reproducing various structural and transport properties of this promising class of materials and predict an exponential increase in cationic diffusion with larger inter-layer distances. The simulations demonstrate the correlation between broadened inter-layer (inter-slab) distances associated with the larger ionic radii of K and Na compared to Li and the enhanced cationic conduction exhibited in K</b><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b> and Na</b><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b> relative to Li</b><sub>2</sub><b>Ni</b><sub>2</sub><b>TeO</b><sub>6</sub><b>. Whence, our findings connect lower potential energy barriers, favourable cationic paths and wider bottleneck size along the cationic diffusion channel within frameworks (comprised of larger mobile cations) to the improved cationic diffusion experimentally observed in honeycomb layered oxides. Furthermore, we elucidate the role of inter-layer distance and cationic size in cationic diffusion. Our theoretical studies reveal the dominance of inter-layer distance over cationic size, a crucial insight into the further performance enhancement of honeycomb layered oxides.</b><br>

Tris(trimethylsilyl) phosphite (TMSPi) as an electrolyte additive for LiNi0.5Co0.2Mn0.3O2 cathode materials at elevated voltage and temperature

2021 ◽  
Author(s):  
Xiao Yu ◽  
Zhiyong Yu ◽  
Jishen Hao ◽  
Hanxing Liu
Keyword(s):  
Discharge Capacity ◽  
Cathode Materials ◽  
Solid Electrolyte Interphase ◽  
Rate Capability ◽  
Electrochemical Performances ◽  
Initial Discharge Capacity ◽  
Capacity Retention ◽  
Electrolyte Additive ◽  
Interface Impedance ◽  
Initial Discharge

Electrolyte additive tris(trimethylsilyl) phosphite (TMSPi) was used to promote the electrochemical performances of LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2 (NCM523) at elevated voltage (4.5 V) and temperature (55[Formula: see text]C). The NCM523 in 2.0 wt.% TMSPi-added electrolyte exhibited a much higher capacity (166.8 mAh/g) than that in the baseline electrolyte (118.3 mAh/g) after 100 cycles under 4.5 V at 30[Formula: see text]C. Simultaneously, the NCM523 with 2.0 wt.% TMSPi showed superior rate capability compared to that without TMSPi. Besides, after 100 cycles at 55[Formula: see text]C under 4.5 V, the discharge capacity retention reached 87.4% for the cell with 2.0 wt.% TMSPi, however, only 24.4% of initial discharge capacity was left for the cell with the baseline electrolyte. A series of analyses (TEM, XPS and EIS) confirmed that TMSPi-derived solid electrolyte interphase (SEI) stabilized the electrode/electrolyte interface and hindered the increase of interface impedance, resulting in obviously enhanced electrochemical performances of NCM523 cathode materials under elevated voltage and/or temperature.

Cationic-Anionic Redox Couple Gradient to Immunize Against Irreversible Processes of Li-rich Layered Oxides

2020 ◽  
Author(s):  
Yi Pei ◽  
Shuang Li ◽  
Qing Chen ◽  
Ruilin Liang ◽  
Matthew Li ◽  
...  
Keyword(s):  
Cathode Materials ◽  
Redox Couple ◽  
Irreversible Processes ◽  
Layered Oxides

The ability of extracting/inserting more than one Li per formula has made Li-rich layered oxides (LLO) one of the most promising cathode materials. However, irreversible transformations triggered by over-delithiation such...

scholarly journals Improved electrochemical performance of SiO2-coated Li-rich layered oxides-Li1.2Ni0.13Mn0.54Co0.13O2

2020 ◽  
Vol 31 (21) ◽  
pp. 19475-19486
Author(s):  
Jeffin James Abraham ◽  
Umair Nisar ◽  
Haya Monawwar ◽  
Aisha Abdul Quddus ◽  
R. A. Shakoor ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Cathode Material ◽  
Sol Gel ◽  
Rate Capability ◽  
Lithium Ion ◽  
Side Reactions ◽  
Operating Voltage ◽  
Layered Oxides ◽  
Capacity Retention ◽  
Xps Characterization

AbstractLithium-rich layered oxides (LLOs) such as Li1.2Ni0.13Mn0.54Co0.13O2 are suitable cathode materials for future lithium-ion batteries (LIBs). Despite some salient advantages, like low cost, ease of fabrication, high capacity, and higher operating voltage, these materials suffer from low cyclic stability and poor capacity retention. Several different techniques have been proposed to address the limitations associated with LLOs. Herein, we report the surface modification of Li1.2Ni0.13Mn0.54Co0.13O2 by utilizing cheap and readily available silica (SiO2) to improve its electrochemical performance. Towards this direction, Li1.2Ni0.13Mn0.54Co0.13O2 was synthesized utilizing a sol–gel process and coated with SiO2 (SiO2 = 1.0 wt%, 1.5 wt%, and 2.0 wt%) employing dry ball milling technique. XRD, SEM, TEM, elemental mapping and XPS characterization techniques confirm the formation of phase pure materials and presence of SiO2 coating layer on the surface of Li1.2Ni0.13Mn0.54Co0.13O2 particles. The electrochemical measurements indicate that the SiO2-coated Li1.2Ni0.13Mn0.54Co0.13O2 materials show improved electrochemical performance in terms of capacity retention and cyclability when compared to the uncoated material. This improvement in electrochemical performance can be related to the prevention of electrolyte decomposition when in direct contact with the surface of charged Li1.2Ni0.13Mn0.54Co0.13O2 cathode material. The SiO2 coating thus prevents the unwanted side reactions between cathode material and the electrolyte. 1.0 wt% SiO2-coated Li1.2Ni0.13Mn0.54Co0.13O2shows the best electrochemical performance in terms of rate capability and capacity retention.

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