MATERIALS CHEMISTRY AND PHYSICS
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2022
·
IF 4.778
Juguo Dai,Lili Luo,Xiaohong Wang,Long Xia,Hongmei Xie,Chunying Yang,Ruipan Wang,Yiting Xu,Lizong Dai
Nowadays, energy conversion devices have gradually gained attention while vigorously developing clean energy. Carbon materials are promising candidates for supercapacitors , but two issues have plagued the researchers. 1) Does the cation radius in the neutral electrolyte significantly impact the electrochemical performance of carbon materials? 2) How to introduce heteroatoms while constructing hollow structures in carbon spheres. This work proposes a facile template free strategy that uses aniline and pyrrole as nitrogen sources to synthesize carbon sphere precursors. High-temperature carbonization combined with alkali treatment leads to the formation of N-doped hollow porous carbon spheres. Robust wall structure (thickness is about 60–80 nm) and ideal surface structure (the specific surface area is 1079.9 m 2 g −1 ) endow the carbon spheres with excellent electrochemical performance and outstanding cycle stability. The specific capacitance of the carbon spheres in Li 2 SO 4 and Na 2 SO 4 electrolytes under negative working potential (−0.8–0 V) are 378.4 and 367.6 F g −1 , respectively, at a current density of 1 A g −1 . After 5000 cycles, the capacitance retentions are 87.1% and 94.8% in Li 2 SO 4 and Na 2 SO 4 electrolytes. We inferred that the cation radius has a negligible effect on the specific capacitance of carbon materials, but has a more significant effect on the cycling stability and capacitance rate performance. It is hoped that this work can provide a reference for the subsequent construction of N-doped hollow carbon spheres and reasonable selection of electrolytes.
研究领域:
材料科学
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电化学
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纳米能源
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功能材料
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储能技术
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 8
·期 1
·670-677
·
IF 1.5
Borong Wu,Yonghuan Ren,Daobin Mu,Cunzhong Zhang,Xiaojiang Liu,Guchang Yang,Feng Wu
A low cost and environment benign salt of sodium chloride (NaCl) was used as an additive in low temperature electrolyte (Lithium hexafluorophosphate(LiPF6) / ethylene carbonate(EC) / propylene carbonate(PC) / ethyl methyl carbonate(EMC) (0.14/0.18/0.68, wt.)) to improve the electrochemical performance of mesocarbon microbeads(MCMB) anode. The initial Li extraction capacity of MCMB electrode was 304.8mAh g -1 in this electrolyte when the content of EC was remarkably reduced for a better conductivity. Whereas, a value of 357.6mAh g -1 was attained in the presence of NaCl additive. The electrochemical performance of MCMB was largely enhanced in the low temperature electrolyte with NaCl. The effect of NaCl additive on the electrode performance was examined by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopic(XPS).
研究领域:
电化学
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材料科学
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能源存储
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锂离子电池
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电极材料
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电解液工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2021
·
IF 9.127
Jingxiong Gao,Songyi Han,Haiming Hua,Jie Wu,Jing Zeng,Yuanyu Sun,Weiping Tang,Shuling Liu,Jinbao Zhao
To optimize the electrochemical behavior of NCM-based high-energy lithium-ion batteries (LIBs) in wide temperature ranges, Phenyl trifluoromethane sulfonate (PTM) is demonstrated as the novel electrolyte additive to enhance the electrochemical behavior of LiNi 0·6 Co 0·2 Mn 0·2 O 2 /graphite cells at 25 °C, −20 °C and 45 °C. The cells with 1.0 wt% PTM-containing electrolyte deliver 80.6% capacity retention after 350 cycles at 25 °C, 73.4% after 100 cycles at −20 °C, and 82.6% after 300 cycles at 45 °C, which are significantly higher than that in standard electrolyte (STD), corresponding to 36.4% at 25 °C, 40.3% at −20 °C, and failure at 45 °C, respectively. According to density functional theory (DFT) simulations and quantitative calculations, the PTM preferentially reduces on the anode and oxidizes on the cathode to participate in the formation of solid electrolyte interphase (SEI) films. In addition, the scanning electron microscopy (SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and other analysis suggest that the formed SEI films are thinner and more stable for the electrolyte containing PTM, and the formed SEI films effectively control the decomposition of carbonate-based electrolytes and greatly decrease the increased resistance during the cycle.
研究领域:
电化学
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材料科学
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能源存储
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锂电池技术
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界面化学
✓ 已验证
DOI
高影响因子
Journal of Energy Chemistry
·
2022
·
IF 13.599
Xin Wu,Xingyu Xiong,Bin Yuan,Jun Liu,Renzong Hu
A good cycling stability is a prerequisite for the application of metal-based materials in lithium-ion batteries (LIBs). However, an abnormal increase in capacity is often observed, which has rarely been focused on in many studies. In our SnSe-Mo-C composite anode, a high reversible capacity of 737.4 mAh g −1 remained after 5000 cycles at 5 A g −1 between 0.01 and 3.0 V versus Li/Li + . However, a continuous capacity increase occurred in the initial cycles, with 1086.9 mAh g −1 after 1000 cycles and 1216.9 mAh g −1 after 1500 cycles, respectively. Further studies revealed that the electrolyte decomposed at high potentials (2.5–3.0 V) and provided additional capacities. The cut-off voltage and electrolyte filling were controlled, which eliminated the impact of electrolyte decomposition, prevented rapid capacity decay, and provided a stable cycling performance for SnSe-Mo-C anodes in LIBs. This work shows that the composite anode is promising for lithium storage and the findings provide new insights into understanding and controlling the phenomenon of capacity increase with cycling in metal-based anode materials.
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
Energy Technology
·
2019
·Vol. 7
·期 4
·1800981
·
IF 3.163
Bangwei Deng,Hao Wang,Xiang Li,Yan Ding,Daming Sun,Jun Ma,Mianzhong Chen,Tao Chen,Feng Gao,Meizhen Qu,Gongchang Peng
Tris(trimethylsilyl)phosphite (TMSPi) has been reported to be an excellent electrolyte additive. However, scarce reports exist on the effect of the charge cutoff potential on the cyclic stability using high-performance LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622)–mesocarbon microbead (MCMB) full cells. Herein, a high-loading and repeatable NCM622–MCMB coin-type full cell is successfully prepared, and the role of TMSPi on such a full cell at charge cutoff potentials of 4.25 and 4.45 V is studied. Theoretical calculations and detailed analyses reveal that it is oxidized in the first charging process due to its unsaturated P—O bonds, thus forming a stable P—O—F-rich cathode electrolyte interphase and preventing severe decomposition of the electrolyte over NCM622 during long-term cycling. In addition, the P—O and Si—O bonds of TMSPi both display HF-scavenging ability. Moreover, TMSPi may react directly with the LiPF 6 -based electrolyte to form some intermediate products that can be reduced on the MCMB electrode, thereby modifying the solid electrolyte interphase and improving the stability of MCMB during lithium intercalation.
研究领域:
电化学
·
材料科学
·
能源存储
·
锂离子电池
·
界面化学
·
电极材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）