scholarly journals Boosting Transport Kinetics of Ions and Electrons Simultaneously by Ti3C2Tx (MXene) Addition for Enhanced Electrochromic Performance

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.

2021 ◽  
Author(s):  
Yu Gao ◽  
Jun Huang ◽  
Yuwen Liu ◽  
Shengli Chen

The discrepancy between the trend in the diffusion coefficient of lithium ion (DLi+) and that in the activation energy of ion hopping signals hidden factors determining ion transport kinetics in...


Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1952 ◽  
Author(s):  
Santanu Mukherjee ◽  
Shakir Bin Mujib ◽  
Davi Soares ◽  
Gurpreet Singh

Sodium ion batteries (SIBs) are being billed as an economical and environmental alternative to lithium ion batteries (LIBs), especially for medium and large-scale stationery and grid storage. However, SIBs suffer from lower capacities, energy density and cycle life performance. Therefore, in order to be more efficient and feasible, novel high-performance electrodes for SIBs need to be developed and researched. This review aims to provide an exhaustive discussion about the state-of-the-art in novel high-performance anodes and cathodes being currently analyzed, and the variety of advantages they demonstrate in various critically important parameters, such as electronic conductivity, structural stability, cycle life, and reversibility.


NANO ◽  
2020 ◽  
pp. 2150005
Author(s):  
Meng Sun ◽  
Zhipeng Cui ◽  
Huanqing Liu ◽  
Sijie Li ◽  
Qingye Zhang ◽  
...  

FeOOH nanorods (NRs) wrapped by reduced graphene oxide (rGO) were fabricated using a facile solvothermal method. When used as anode materials for lithium-ion batteries (LIBs), the FeOOH NRs/rGO composites show a higher capacity (490[Formula: see text]mAh g[Formula: see text] after 100 cycles at a current density of 100[Formula: see text]mA g[Formula: see text] and better rate capability than pure FeOOH NRs. The enhanced electrochemical performance can be ascribed to the hybrid structure of FeOOH and rGO. On one hand, the introduction of rGO can improve electronic conductivity and reduce charge-transfer resistance for electrode materials. On the other hand, the distinctive structure (FeOOH NRs surrounded by flexible rGO) can effectively buffer large volume change during the Li[Formula: see text] insertion/extraction process. Our work provides a feasible strategy to obtain high-performance LIBs.


Author(s):  
E. Thauer ◽  
G. S. Zakharova ◽  
E. I. Andreikov ◽  
V. Adam ◽  
S. A. Wegener ◽  
...  

AbstractFor the first time, ZnO/C composites were synthesized using zinc glycerolate as a precursor through one-step calcination under a nitrogen atmosphere. The effect of the heat treatment conditions on the structure, composition, morphology as well as on the electrochemical properties regarding application in lithium-ion batteries are investigated. The products obtained by calcination of the precursor in nitrogen at 400—800 °C consist of zinc oxide nanoparticles and amorphous carbon that is in-situ generated from organic components of the glycerolate precursor. When used as anode material for lithium-ion batteries, the as-prepared ZnO/C composite synthesized at a calcination temperature of 700 °C delivers initial discharge and charge capacities of 1061 and 671 mAh g−1 at a current rate of 100 mA g−1 and hence 1.5 times more than bare ZnO, which reaches only 749/439 mAh g−1. The native carbon improves the conductivity, allowing efficient electronic conductivity and Li-ion diffusion. By means of ex-situ XRD studies a two-step storage mechanism is proven.


2014 ◽  
Vol 07 (06) ◽  
pp. 1440013 ◽  
Author(s):  
Xiangjun Li ◽  
Hongxing Xin ◽  
Xiaoying Qin ◽  
Xueqin Yuan ◽  
Di Li ◽  
...  

Lithium and Mn rich solid solution materials Li [ Li 0.26 Ni 0.07 Co 0.07 Mn 0.56] O 2 were synthesized by a carbonate co-precipitation method and modified with a layer of graphene. The graphene-modified cathodes exhibit improved rate capability and cycling performance as compared to the bare cathodes. Electrochemical impedance spectroscopy (EIS) analyses reveal that the improved electrochemical performances are due to acceleration kinetics of lithium-ion diffusion and the charge transfer reaction of the graphene-modified cathodes.


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.


2021 ◽  
Vol 1028 ◽  
pp. 138-143
Author(s):  
Iman Rahayu ◽  
Anggi Suprabawati ◽  
Vina M. Puspitasari ◽  
Sahrul Hidayat ◽  
Atiek Rostika Noviyanti

Lithium ion batteries with LiFePO4 cathode have become the focus of research because they are eco-friendly, stable, high average voltage (3.5 V), and high theoretical capacity (170 mAh/g). However, LiFePO4 has disadvantages such as low electrical conductivity (~10-9 S/cm) and low lithium ion diffusion coefficient (~10-14-10-15 cm2/s) that can inhibit its application as a lithium ion battery cathode material. To increase the electronic conductivity of LiFePO4, it can be done by adding carbon as a coating material, then doping gadolinium metal ions because it has a radius similar to Fe, and increasing sintering temperature. Optimizing the sintering temperature can control particle growth and research was study the sintering temperature of the electronic conductivity of LiFeGdPO4/C and obtain the optimum sintering temperature at LiFeGdPO4/C. The carbothermal reduction method used in synthesis, with a variation of sintering temperature of 800°C, 830°C, 850°C, 870°C, and 900°C using reagents LiH2PO4, Fe2O3, Gd2O3, and carbon black. Furthermore the samples were characterized using XRD, SEM-EDS, and four-point probes. The results of the study were expected to increase the conductivity of LiFePO4. The results show the effect of sintering temperature can increase the electronic conductivity of LiFeGdPO4/C. Samples with a sintering temperature 850°C have the highest conductivity among all temperature variations with a value of 1.11 × 10-5 S cm-1.


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