Improvement of Electrochemical Performance and Thermal Stability by Reducing Residual Lithium Hydroxide on LiNi0.8Co0.1Mn0.1O2 Active Material using Amorphous Carbon Coating

2018 ◽  
Vol 21 (2) ◽  
pp. 071-075 ◽  
Author(s):  
Ji-Woong Shin ◽  
Jong-Tae Son

Using LiNi0.8Co0.1Mn0.1O2 as a starting material, a surface-modified cathode material was obtained by coating it with a nanolayer of amorphous carbon, where the added C12H22O11 (sugar) was transformed to Li2CO3 compounds after reacting with residual LiOH on the surface. A thin and uniformly smooth nanolayer (35 nm thick) was observed on the surface of the LiNi0.8Co0.1Mn0.1O2, as confirmed by transmission electron microscopy (TEM). The amount of residual lithium hydroxide (LiOH) was significantly reduced through the formation of lithium carbonate (Li2CO3). As a result, carbon-coated LiNi0.8Co0.1Mn0.1O2 exhibited noticeable improvement in capacity and rate capability and much lower exothermic heat in the charged state at 4.3V. The improved electrochemical performance and thermal stability are attributed to the carbon coating, which reduced the residual lithium hydroxide, protected the cathode material from reacting with the electrolyte, and slowing the incrassation of the solid electrolyte interphase (SEI) film on the surfaces of the oxide particles.C12H22O11 + 12O2 → 12CO2 + 11H2OPACS number: 73.20.At

2020 ◽  
Vol 31 (21) ◽  
pp. 19475-19486
Author(s):  
Jeffin James Abraham ◽  
Umair Nisar ◽  
Haya Monawwar ◽  
Aisha Abdul Quddus ◽  
R. A. Shakoor ◽  
...  

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.


NANO ◽  
2019 ◽  
Vol 14 (03) ◽  
pp. 1950037 ◽  
Author(s):  
Bingning Wang ◽  
Xuehua Liu ◽  
Binghui Xu ◽  
Yanhui Li ◽  
Dan Xiu ◽  
...  

Three-dimensional reduced graphene oxide (RGO) matrix decorated with nanoflowers of layered MoS2 (denoted as 3D MoS2/RGO) have been synthesized via a facile one-pot stepwise hydrothermal method. Graphene oxide (GO) is used as precursor of RGO and a 3D GO network is formed in the first-step of hydrothermal treatment. At the second stage of hydrothermal treatment, nanoflowers of layered MoS2 form and anchor on the surface of previously formed 3D RGO network. In this preparation, thiourea not only induces the formation of the 3D architecture at a relatively low temperature, but also works as sulfur precursor of MoS2. The synthesized composites have been investigated with XRD, SEM, TEM, Raman spectra, TGA, N2 sorption technique and electrochemical measurements. In comparison with normal MoS2/RGO composites, the 3D MoS2/RGO composite shows improved electrochemical performance as anode material for lithium-ion batteries. A high reversible capacity of 930[Formula: see text]mAh[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] after 130 cycles under a current density of 200[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] as well as good rate capability and superior cyclic stability have been observed. The superior electrochemical performance of the 3D MoS2/RGO composite as anode active material for lithium-ion battery is ascribed to its robust 3D structures, enhanced surface area and the synergistic effect between graphene matrix and the MoS2 nanoflowers subunit.


2018 ◽  
Vol 783 ◽  
pp. 137-143
Author(s):  
Yong Tao Zhang ◽  
Xiao Li Hu

The lithium-ion battery is widely and increasingly used in many portable electronic devices and high-power systems in the modern society. Currently, it is significant to develop excellent cathode materials to meet stringent standards for batteries. In this paper, recent developments were reviewed for several typical cathode materials with high voltages and good capacities. These cathode materials referred to LiCoO2, LiNiO2, LiMn2O4, LiMPO4 (M=Fe, Mn, Co and Ni, et al), and their composites. The technical bottlenecks about the cathode material is required to be conquered. For instance, LiCoO2 and LiNiO2 have high coulombic capacity and good cycling characteristics, but are costly and exhibit poor thermal stability. Simultaneously, LiMn2O4 exhibit good thermal stability, high voltage and high rate capability, but have low capacity. Thus it is advantageous to produce a composite which shares the benefits of both materials. The composite cathode material is superior over any single electrode material because the former has more balanced performance, and therefore, is promising to manufacture the next generation of batteries.


RSC Advances ◽  
2018 ◽  
Vol 8 (51) ◽  
pp. 28978-28986 ◽  
Author(s):  
Yifang Wu ◽  
Shaokun Chong ◽  
Yongning Liu ◽  
ShengWu Guo ◽  
Pengwei Wang ◽  
...  

C18BF15 was first adopted as a boron source and has demonstrated its clear modification effects, as shown by the high rate capability.


RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44296-44302 ◽  
Author(s):  
Weiwei Jiang ◽  
Mengqiang Wu ◽  
Fei Liu ◽  
Jian Yang ◽  
Tingting Feng

Asphalt-derived and glucose-derived carbon proved to be soft carbon-coating (SCC) and hard carbon-coating (HCC), and it was found that LFP/SCC showed a superior performance in capacity and rate capability than that of LFP/HCC.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yumei Gao ◽  
Yuchong Hui ◽  
Hang Yin

The Li-rich Mn-based oxide Li1.2Mn0.54Ni0.13Co0.13O2 has been extensively studied as a cathode material of the battery module for new optoelectronic devices. To improve and enhance the electrochemical performance, sodium doping is one of the effective approaches. According to the density functional theory of first-principles, the band gap, partial density of states, lithiation formation energy, electron density difference, and potential energy of electrons for Li1.2−xNaxMn0.54Ni0.13Co0.13O2 were simulated with Materials Studio, Nanodcal, and Matlab. When the sodium doping amount x = 0.10 mol, simulations show that Li1.2−xNaxMn0.54Ni0.13Co0.13O2 has a better conductivity. The potential maps of Li1.2−xNaxMn0.54Ni0.13Co0.13O2 obtained in Matlab demonstrate that the potential barrier is lower and the rate capability is enhanced after sodium doping. Results of analyses and calculations agree with the experimental result of Chaofan Yang’s group. This theoretical method could be a great avenue for the investigation of the battery application of new optoelectronic devices. Also, our findings could give some theoretical guidance for the subsequent electrochemical performance study on doping in the field of lithium-ion batteries.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jianjun Song ◽  
Ying Zhang ◽  
Guangjie Shao

Supervalent cation doping and metal oxide coating are the most efficacious and popular methods to optimize the property of LiFePO4lithium battery material. Mg-doped and MgO-coated LiFePO4/C were synthesized to analyze their individual influence on the electrochemical performance of active material. The specific capacity and rate capability of LiFePO4/C are improved by both MgO coating and Mg doping, especially the Mg-doped sample—Li0.985Mg0.015FePO4/C, whose discharge capacity is up to 163 mAh g−1, 145.5 mAh g−1, 128.3 mAh g−1, and 103.7 mAh g−1at 1 C, 2 C, 5 C, and 10 C, respectively. The cyclic life of electrode is obviously increased by MgO surface modification, and the discharge capacity retention rate of sample LiFePO4/C-MgO2.5is up to 104.2% after 100 cycles. Comparing samples modified by these two methods, Mg doping is more prominent on prompting the capacity and rate capability of LiFePO4, while MgO coating is superior in terms of improving cyclic performance.


Sign in / Sign up

Export Citation Format

Share Document