Oxygen Vacancies Boosting Lithium-Ion Diffusion Kinetics of Lithium Germanate for High-Performance Lithium Storage

Author(s):  
Long Li ◽  
Tao Meng ◽  
Jie Wang ◽  
Baoguang Mao ◽  
Jingbin Huang ◽  
...  
Nanoscale ◽  
2020 ◽  
Vol 12 (16) ◽  
pp. 8858-8866
Author(s):  
Qiwang Jiang ◽  
Jie Wang ◽  
Yan Jiang ◽  
Long Li ◽  
Xingzhong Cao ◽  
...  

Selenium vacancy-rich and carbon-free VSe2 nanosheets achieve excellent lithium storage performance due to significantly enhanced lithium-ion diffusion rate and electrochemical active sites induced by the Se vacancies.


NANO ◽  
2020 ◽  
Vol 15 (04) ◽  
pp. 2050051
Author(s):  
Rudong Zheng ◽  
Lili Wu ◽  
Jiabao Zhao ◽  
Chuncheng Zhu ◽  
Hong Gao

Ti3C2Tx, a new type of two-dimensional material, is a prospective anode material in lithium-ion batteries (LIBs) for its low lithium-ion diffusion barrier, high conductivity and many other excellent properties. In this paper, multilayer Ti3C2Tx and delaminated Ti3C2Tx samples are prepared by etching Ti3AlC2 powder with HF and [Formula: see text], respectively. We explore the application of the two samples in LIBs, and analyze their electrochemical behavior and kinetic mechanism. At the current densities of 0.1[Formula: see text]A[Formula: see text]g[Formula: see text], the delaminated Ti3C2Tx electrode delivered higher capacities of 255[Formula: see text]mAh[Formula: see text]g[Formula: see text] than multilayer Ti3C2Tx electrode (100[Formula: see text]mAh[Formula: see text]g[Formula: see text]). Even after 1000 cycles, the specific capacity of the delaminated Ti3C2Tx is still up to 205[Formula: see text]mAh[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text]g[Formula: see text]. This work proves the great potential of the delaminated Ti3C2Tx for lithium-ion storage.


2019 ◽  
Vol 7 (13) ◽  
pp. 7644-7653 ◽  
Author(s):  
Jingyi Wu ◽  
Na You ◽  
Xiongwei Li ◽  
Hongxia Zeng ◽  
Shuai Li ◽  
...  

The synergistic effect of the SiO2@MoS2 core–shell nanocomposite simultaneously facilitates Li+ diffusion and provides triple confinement of polysulfides.


2019 ◽  
Vol 9 (20) ◽  
pp. 4218 ◽  
Author(s):  
Yijing Zheng ◽  
Lisa Pfäffl ◽  
Hans Jürgen Seifert ◽  
Wilhelm Pfleging

For the development of thick film graphite electrodes, a 3D battery concept is applied, which significantly improves lithium-ion diffusion kinetics, high-rate capability, and cell lifetime and reduces mechanical tensions. Our current research indicates that 3D architectures of anode materials can prevent cells from capacity fading at high C-rates and improve cell lifespan. For the further research and development of 3D battery concepts, it is important to scientifically understand the influence of laser-generated 3D anode architectures on lithium distribution during charging and discharging at elevated C-rates. Laser-induced breakdown spectroscopy (LIBS) is applied post-mortem for quantitatively studying the lithium concentration profiles within the entire structured and unstructured graphite electrodes. Space-resolved LIBS measurements revealed that less lithium-ion content could be detected in structured electrodes at delithiated state in comparison to unstructured electrodes. This result indicates that 3D architectures established on anode electrodes can accelerate the lithium-ion extraction process and reduce the formation of inactive materials during electrochemical cycling. Furthermore, LIBS measurements showed that at high C-rates, lithium-ion concentration is increased along the contour of laser-generated structures indicating enhanced lithium-ion diffusion kinetics for 3D anode materials. This result is correlated with significantly increased capacity retention. Moreover, the lithium-ion distribution profiles provide meaningful information about optimizing the electrode architecture with respect to film thickness, pitch distance, and battery usage scenario.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Wenting Wu ◽  
Huajing Fang ◽  
Hailong Ma ◽  
Liangliang Wu ◽  
Wenqing Zhang ◽  
...  

Abstract Electrochromic technology plays a significant role in energy conservation, while its performance is greatly limited by the transport behavior of ions and electrons. Hence, an electrochromic system with overall excellent performances still need to be explored. Initially motivated by the high ionic and electronic conductivity of transition metal carbide or nitride (MXene), we design a feasible procedure to synthesize the MXene/WO3−x composite electrochromic film. The consequently boosted electrochromic performances prove that the addition of MXene is an effective strategy for simultaneously enhancing electrons and ions transport behavior in electrochromic layer. The MXene/WO3−x electrochromic device exhibits enhanced transmittance modulation and coloration efficiency (60.4%, 69.1 cm2 C−1), higher diffusion coefficient of Li+ and excellent cycling stability (200 cycles) over the pure WO3−x device. Meanwhile, numerical stimulation theoretically explores the mechanism and kinetics of the lithium ion diffusion, and proves the spatial and time distributions of higher Li+ concentration in MXene/WO3−x composite electrochromic layer. Both experiments and theoretical data reveal that the addition of MXene is effective to promote the transport kinetics of ions and electrons simultaneously and thus realizing a high-performance electrochromic device. This work opens new avenues for electrochromic materials design and deepens the study of kinetics mechanism of ion diffusion in electrochromic devices.


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