JOURNAL OF POWER SOURCES
·
2016
·
IF 6.333
Zihao Li,Xiaogang Li,Youhao Liao,Xiaoping Li,Weishan Li
We report a novel composite of sulfur loaded in micropore-rich carbon aerogel (CA-S), as cathode of lithium-sulfur battery. Carbon aerogel (CA) is synthesized through phenol-formaldehyde reaction with a low catalyst concentration and carbonization under high temperature, and loaded with sulfur via chemical deposition and heat treatment. The physical properties of the resulting CA and the electrochemical performances of the resulting CA-S are investigated by scanning electron microscopy, thermal gravimetric analysis , Brunauer-Emmett-Teller characterization, electrochemical impedance spectroscopy , and galvanostatic discharge/charge test, with a comparison of a common carbon material, acetylene black (AB), and sulfur loaded in AB (AB-S). It is found that the CA is micropore-rich with micropore volume over 66% of total pore volume , and the CA-S exhibits significantly improved cyclic stability compared with AB-S. The improved performance of CA-S is attributed to the confinement of the micropores in CA to small sulfur allotropes and corresponding lithium sulfides.
研究领域:
电化学
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能源材料
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纳米材料
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储能技术
✓ 已验证
DOI
高影响因子
Small
·
2018
·Vol. 14
·期 11
·1703279
·
IF 9.598
Qian Wang,Minghui Yang,Zhen-Bo Wang,Chao Li,Da-Ming Gu
Shuttle effect of the dissolved intermediates is regarded as the primary cause that leads to fast capacity degradation of Li–S battery. Herein, a microporous carbon-coated sulfur composite with novel rambutan shape (R-S@MPC) is synthesized from microporous carbon-coated rambutan-like zinc sulfide (R-ZnS@MPC), via an in situ oxidation process. The R-ZnS is employed as both template and sulfur precursor. The carbon frame of R-S@MPC composite possesses three kinds of pores that are distinctly separated from each other in space and are endowed with the exclusive functions. The central macropore serves as buffer pool to accommodate the dissolved lithium polysulfides (LPSs) and volumetric variation during cycling. The marginal straight-through mesoporous, connected with the central macropore, takes the responsibility of sulfur storage. The micropores, evenly distributed in the outer carbon shell of the as-synthesized R-S@MPC, enable the blockage of LPSs. These pores are expected to perform their respective single function, and collaborate synergistically to suppress the sulfur loss. Therefore, it delivers an outstanding cycling stability, decay rate of 0.013% cycle −1 after 500 cycles at 1 C, when the sulfur loading is kept at 4 mg cm −2 .
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
功能材料
✓ 已验证
DOI
高影响因子
Nano Energy
·
2017
·
IF 12.343
Qizhen Zhu,Qian Zhao,Yabin An,Babak Anasori,Haoran Wang,Bin Xu
Lithium-sulfur (Li-S) batteries are one of the most promising energy storage systems with high energy density . However, they suffer from fast capacity fading due to the shuttle of the dissolved polysulfides . Using small sulfur molecules (S 2–4 ) as cathodes can avoid the shuttle problem, but the preparation of ultra-microporous carbon to encapsulate S 2–4 is challenging. Here, we report a Li-S battery with an excellent cycling performance by using a unique ultra-microporous carbon (UMC) with a uniform pore size of 0.55 nm. The UMC was synthesized from PVDF via a facile pyrolysis process to only accommodate small S 2–4 molecules and eliminate large S 8 molecules. This S/UMC composite electrode is compatible with the carbonate-based electrolyte used in Li-S batteries. The resulting battery shows a typical discharging profile with only one long potential plateau because the reductions from cyclo-S 8 to dissolved polysulfides and consequence shuttle problem are avoided. The S/UMC composite retains a capacity of about 852 mAh g −1 and Coulombic efficiency approaching 100% after 150 cycles at 0.1 C and delivers a long-term cycling at 1 C for 1000 cycles with only around 0.03% capacity loss per cycle. We also tested this S/UMC composite electrode in Na-S systems and observed similar electrochemical behaviour. These results indicate that the S/UMC composite is a promising candidate as an electrode material in Li-S and Na-S batteries and related systems.
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
DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 31
·13906-13913
·
IF 4.197
Kunpeng Song,Peng Liu,Jingyu Wang,Lei Pang,Jian Chen,Irshad Hussain,Bien Tan,Tao Li
Novel dual-porous carbon-supported palladium nanoparticle (Pd NP) catalysts were prepared by sequential carbonization and reduction of microporous organic polymer-encaged PdCl2. The diverse pore structure of microporous organic polymers provides a reservoir for the palladium precursors and prevents Pd NPs from sintering during the carbonization and reaction. The microporous structure has a significant effect on the size and dispersion of palladium NPs. The average size of the Pd NPs (in the range of 4–6 nm) was tuned by changing the pore size distribution and the carbonization temperature. The resulting carbon-supported Pd NPs were characterized by TEM, BET, XRD, and XPS and the Pd loading was calculated by AAS. The encaged Pd NP catalysts prepared by this methodology exhibited outstanding stability and reusability in the Heck reaction and could be reused at least 10 times without appreciable loss of activity.
研究领域:
材料化学
·
纳米催化
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有机合成方法学
·
多孔材料
·
绿色化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）