Optimization of mesoporous carbon structures for lithium-sulfur battery applications
Optimization of mesoporous carbon structures for lithium-sulfur battery applications
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DOI：
10.1039/c1jm12979a
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发表时间：
2011-01-01
影响因子：
--
通讯作者：
Liu, Jun
中科院分区：
文献类型：
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作者：
Li, Xiaolin;Cao, Yuliang;Liu, Jun
研究了可调孔径（22 nm、12 nm、7 nm和3 nm）和孔体积(1.3 ~ 4.8 cm（3) g(-1)）含硫介孔碳（MC）作为锂硫（Li-S）电池介孔碳-硫（MCS）复合电极。对这些MCS复合材料的系统研究表明，孔径较大的MCS复合材料可以容纳更高的最大硫负荷，但总体而言，不同的MCS复合材料在完全充硫条件下的电池性能非常相似（即硫负荷接近单个MC的孔径所设定的最大极限，因此每个MC的孔隙都被硫完全填充）。对于相同的MC，部分充硫（即硫负荷低于最大限度的条件，因此孔中仅部分充满硫）导致初始放电容量和循环稳定性的提高，这可能是因为电化学反应过程中电和离子传输的改善。基于这一认识，设计了一种具有大孔体积、部分硫填充和新型表面改性的MCS复合电极，用于锂硫电池。使用MC (22 nm, 4.8 cm（3) g(-1)）和商用Clevios P(聚（3,4-乙烯二氧噻吩）聚苯乙烯磺酸盐（PEDT/PSS）涂层，在0.1 C速率下，获得了类似于1390 mA h g（-1）的初始容量和类似于840 mA h g（-1）的容量保持。
Mesoporous carbon (MC) with tunable pore sizes (22 nm, 12 nm, 7 nm, and 3 nm) and pore volumes (from 1.3 to 4.8 cm(3) g(-1)) containing sulfur in the pores was studied as a mesoporous carbon-sulfur (MCS) composite electrode for lithium-sulfur (Li-S) batteries. Systematic investigation of these MCS composites reveals that MC with a larger pore volume can hold a higher maximum sulfur loading, but overall the battery performance is very similar for different MCS composites at full sulfur-filling conditions (i.e., the condition at which the sulfur loading approaches the maximum limit set by the pore volume of the individual MC and, therefore, the pores of each MC are fully filled by sulfur). For the same MC, partial sulfur-filling (i.e., the condition at which the sulfur loading is lower than the maximum limit and, therefore, the pores are only partially filled with sulfur) leads to an improved initial discharge capacity and cycle stability, probably because of improved electrical and ionic transport during electrochemical reactions. Based on this understanding, an MCS composite electrode using MC with a large pore volume, partial sulfur filling, and a novel surface modification was designed for Li-S batteries. An initial capacity of similar to 1390 mA h g(-1) (based on sulfur) and a capacity retention of similar to 840 mA h g(-1) over 100 cycles at a 0.1 C rate were obtained using MC (22 nm, 4.8 cm(3) g(-1)) with 50 wt% sulfur loading and a commercially available Clevios P (poly(3,4-ethylenedioxythiophene)poly (styrenesulfonate) (PEDT/PSS)) coating.