MoS2/C composites are considered to have great application potential in sodium-ion batteries(SIBs).It is a challenging and meaningful subject that developing high-performance anode materials via combining MoS2 and car...MoS2/C composites are considered to have great application potential in sodium-ion batteries(SIBs).It is a challenging and meaningful subject that developing high-performance anode materials via combining MoS2 and carbon effectively to give free rein to their advantages in sodium ion storage.In this work,a novel MoS2-C material was designed by using cellulose nanocrystals(CNCs)as low-cost and green carbon source.3 D hierarchical microspheres(200-250 nm)constructed by ultrathin MoS2-C nanosheets were synthesized by synchronizing the pre-carbonization of CNCs with the formation of MoS2 in hydrothermal reaction and subsequent pyrolysis process.It is found that the ultrathin MoS2-C nanosheets were composed of CNCs-derived short-range ordered carbon and few-layered MoS2.Benefiting from the unique structure and robust combination of MoS2 and CNCs-derived carbon,the ultrathin MoS2-C nanosheets composite was proved to have excellent cycling stability and superior rate performance in sodium-ion half-cell test and have high first reversible specific capacity of 397.9 m Ah/g in full-cell test.This work provides a significant and effective pathway to prepare MoS2-C materials with excellent electrochemical performance for the application in large-scale energy storage systems.展开更多
以钼酸钠(Na_2MoO_4·2H_2O)、硫脲(NH_2CSNH_2)、CTAB为原料,利用水热法合成了MoS_2/C球状纳米花复合材料。通过XRD、SEM、TEM、TG等分析测试方法,研究了不同CTAB添加量对MoS_2/C复合材料的微观结构、表面形貌的影响规律,结果显示...以钼酸钠(Na_2MoO_4·2H_2O)、硫脲(NH_2CSNH_2)、CTAB为原料,利用水热法合成了MoS_2/C球状纳米花复合材料。通过XRD、SEM、TEM、TG等分析测试方法,研究了不同CTAB添加量对MoS_2/C复合材料的微观结构、表面形貌的影响规律,结果显示,有部分无定形碳嵌入了MoS_2层间,并抑制了MoS_2(002)面的堆积。电化学测试表明:与纯MoS_2相比,MoS_2/C复合材料具有更好的电化学性能,当加入0.025 g CTAB时首次放电比容量达到730 m Ah/g,在100 m A/g的电流密度下经过100次循环比容量稳定在415 m Ah/g。在此基础上讨论了MoS_2/C球状纳米花复合材料的可能生长机理以及对材料电化学性能的影响规律。展开更多
As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase co...As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase conversion that occurs during the charge-discharge process,particularly the deposition of solid Li2S from the liquid-phase polysulfides,which greatly limits its practical application.In this paper,edge-rich MoS2/C hollow microspheres(Edg-MoS2/C HMs)were designed and used to functionalize separator for Li-S battery,resulting in the uniform deposition of Li2S.The microspheres were fabricated through the facile hydrothermal treatment of MoO3-aniline nanowires and a subsequent carbonization process.The obtained Edg-MoS2/C HMs have a strong chemical absorption capability and high density of Li2S binding sites,and exhibit excellent electrocatalytic performance and can effectively hinder the polysulfide shuttle effect and guide the uniform nucleation and growth of Li2S.Furthermore,we demonstrate that the Edg-MoS2/C HMs can effectively regulate the deposition of Li2S and significantly improve the reversibility of the phase conversion of the active sulfur species,especially at high sulfur loadings and high C-rates.As a result,a cell containing a separator functionalized with Edg-MoS2/C HMs exhibited an initial discharge capacity of 935 mAh g-1 at 1.0 C and maintained a capacity of 494 mAh g-1 after 1000 cycles with a sulfur loading of 1.7 mg cm-2.Impressively,at a high sulfur loading of 6.1 mg cm-2 and high rate of 0.5 C,the cell still delivered a high reversible discharge capacity of 478 mAh g-1 after 300 cycles.This work provides fresh insights into energy storage systems related to complex phase conversions.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51974114,51672075,and 21908049)Natural Science Foundation of Hunan Province and the Fundamental Research Funds for the Central Universities。
文摘MoS2/C composites are considered to have great application potential in sodium-ion batteries(SIBs).It is a challenging and meaningful subject that developing high-performance anode materials via combining MoS2 and carbon effectively to give free rein to their advantages in sodium ion storage.In this work,a novel MoS2-C material was designed by using cellulose nanocrystals(CNCs)as low-cost and green carbon source.3 D hierarchical microspheres(200-250 nm)constructed by ultrathin MoS2-C nanosheets were synthesized by synchronizing the pre-carbonization of CNCs with the formation of MoS2 in hydrothermal reaction and subsequent pyrolysis process.It is found that the ultrathin MoS2-C nanosheets were composed of CNCs-derived short-range ordered carbon and few-layered MoS2.Benefiting from the unique structure and robust combination of MoS2 and CNCs-derived carbon,the ultrathin MoS2-C nanosheets composite was proved to have excellent cycling stability and superior rate performance in sodium-ion half-cell test and have high first reversible specific capacity of 397.9 m Ah/g in full-cell test.This work provides a significant and effective pathway to prepare MoS2-C materials with excellent electrochemical performance for the application in large-scale energy storage systems.
文摘以钼酸钠(Na_2MoO_4·2H_2O)、硫脲(NH_2CSNH_2)、CTAB为原料,利用水热法合成了MoS_2/C球状纳米花复合材料。通过XRD、SEM、TEM、TG等分析测试方法,研究了不同CTAB添加量对MoS_2/C复合材料的微观结构、表面形貌的影响规律,结果显示,有部分无定形碳嵌入了MoS_2层间,并抑制了MoS_2(002)面的堆积。电化学测试表明:与纯MoS_2相比,MoS_2/C复合材料具有更好的电化学性能,当加入0.025 g CTAB时首次放电比容量达到730 m Ah/g,在100 m A/g的电流密度下经过100次循环比容量稳定在415 m Ah/g。在此基础上讨论了MoS_2/C球状纳米花复合材料的可能生长机理以及对材料电化学性能的影响规律。
基金financially supported by National Natural Science Foundation of China (No. 51672083)Program of Shanghai Academic/Technology Research Leader (18XD1401400)+3 种基金Basic Research Program of Shanghai (17JC1404702)Leading talents in Shanghai in 2018The 111 project (B14018)the Fundamental Research Funds for the Central Universities (222201718002)
文摘As promising energy storage systems,lithium-sulfur(Li-S)batteries have attracted significant attention because of their ultra-high energy densities.However,Li-S battery suffers problems related to the complex phase conversion that occurs during the charge-discharge process,particularly the deposition of solid Li2S from the liquid-phase polysulfides,which greatly limits its practical application.In this paper,edge-rich MoS2/C hollow microspheres(Edg-MoS2/C HMs)were designed and used to functionalize separator for Li-S battery,resulting in the uniform deposition of Li2S.The microspheres were fabricated through the facile hydrothermal treatment of MoO3-aniline nanowires and a subsequent carbonization process.The obtained Edg-MoS2/C HMs have a strong chemical absorption capability and high density of Li2S binding sites,and exhibit excellent electrocatalytic performance and can effectively hinder the polysulfide shuttle effect and guide the uniform nucleation and growth of Li2S.Furthermore,we demonstrate that the Edg-MoS2/C HMs can effectively regulate the deposition of Li2S and significantly improve the reversibility of the phase conversion of the active sulfur species,especially at high sulfur loadings and high C-rates.As a result,a cell containing a separator functionalized with Edg-MoS2/C HMs exhibited an initial discharge capacity of 935 mAh g-1 at 1.0 C and maintained a capacity of 494 mAh g-1 after 1000 cycles with a sulfur loading of 1.7 mg cm-2.Impressively,at a high sulfur loading of 6.1 mg cm-2 and high rate of 0.5 C,the cell still delivered a high reversible discharge capacity of 478 mAh g-1 after 300 cycles.This work provides fresh insights into energy storage systems related to complex phase conversions.
