Swollen Ammoniated MoS2 with 1T/2H Hybrid Phases for High -Rate Electrochemical Energy Storage
Swollen Ammoniated MoS2 with 1T/2H Hybrid Phases for High -Rate Electrochemical Energy Storage
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用于高速电化学储能的 1T/2H 混合相溶胀氨化 MoS2
DOI：
10.1021/acssuschemeng.6b02863
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发表时间：
2017-03-01
影响因子：
8.4
通讯作者：
Fang, Baizeng
中科院分区：
文献类型：
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作者：
Wang, Dezhi;Xiao, Yuanyuan;Fang, Baizeng
由于其与石墨相似的层状结构，二硫化钼作为锂离子电池和超级电容器的电极材料已被广泛探索，但其能量存储能力受到较差的电/离子传导性和固有层状结构之间的传输的严重阻碍。在此，我们提出了一种新型的具有1T/2H混合相的膨胀氨化MoS2（MoS2-A），它具有高浓度的1T相和独特的膨胀层状结构，作为超级电容器电极材料。所获得的MoS2-A表现出优异的电荷存储性能，具有独特的赝电容行为，包括表面氧化还原反应和扩散插层，即使扫描速度从1到100 mV s(-1)提高100倍，比电容的保留率仍可达到58.5%，表现出超高的倍率能力。此外，该超级电容器电极还表现出良好的循环稳定性，2000次循环后保持率为95.4%。 MoS2-A出色的电化学性能应归因于金属IT相的存在，该相有利于高导电性，以及原位插层物质产生的具有0.99 nm扩大层间空间的膨胀层状结构，有利于电解质离子的快速可逆扩散插层。
Because of its lamellar structure similar to that of graphite, molybdenum disulfide has been widely explored as a lithium-ion battery and supercapacitor electrode material, but its energy storage ability is strongly hindered by the poor electrical/ionic conductivity and transfer among the intrinsic lamellar structures. Herein we propose a novel swollen ammoniated MoS2 with 1T/2H hybrid phases (MoS2-A), which possesses a high concentration of 1T phase and unique expanded lamellar structures, as a supercapacitor electrode material. The obtained MoS2-A reveals superior charge-storage performance with distinct pseudocapacitive behavior, including surface redox reaction and diffusive intercalation, and even when the scan speed is increased 100-fold from 1 to 100 mV s(-1), the retention ratio of the specific capacitance can still reach 58.5%, demonstrating a superhigh rate capability. Moreover, this supercapacitor electrode also exhibits good cycling stability with a retention ratio of 95.4% after 2000 cycles. The outstanding electrochemical performance of MoS2-A should be ascribed to the existence of the metallic IT phase, which favors high electrical conductivity, and the swollen lamellar structures possessing an enlarged interlayer space of 0.99 nm created by in situ intercalated species, facilitating the fast and reversible diffusive intercalation of electrolyte ions.