Constructing heterojunction is a promising way to improve the charge transfer efficiency and can thus promote the electrochemical properties.Herein,a facile and effective epitaxial-like growth strategy is applied to N...Constructing heterojunction is a promising way to improve the charge transfer efficiency and can thus promote the electrochemical properties.Herein,a facile and effective epitaxial-like growth strategy is applied to NiSe2 nano-octahe-dra to fabricate the NiSe2-(100)/Ni(OH)2-(110)heterojunction.The heterojunction composite and Ni(OH)2(performing high electrochemical activity)is ideal high-rate battery-type supercapacitor electrode.The NiSe2/Ni(OH)2 electrode exhibits a high specific capacity of 909 C g^-1 at 1 A g^-1 and 597 C g^-1 at 20 A g^-1.The assembled asymmetric supercapacitor composed of the NiSe2/Ni(OH)2 cathode and p-phenylenediamine-functional reduced graphene oxide anode achieves an ultrahigh specific capacity of 303 C g^-1 at 1 A g^-1 and a superior energy density of 76.1 Wh kg^-1 at 906 W kg^-1,as well as an outstanding cycling stability of 82%retention for 8000 cycles at 10 A g^-1.To the best of our knowledge,this is the first example of NiSe2/Ni(OH)2 heterojunction exhibiting such remarkable supercapacitor performance.This work not only provides a promising candidate for next-generation energy storage device but also offers a possible universal strategy to fabricate metal selenides/metal hydroxides heterojunctions.展开更多
金属硫系化合物作为水相锌电池的高性能阴极具有很大的潜力.然而,低可达表面和剧烈的体积膨胀限制了其整体性能和实际应用.为此,采用相工程策略结合空心结构设计,调控OH−在电极表面的吸附/脱附,能显著提高电极的整体电化学性能.本研究...金属硫系化合物作为水相锌电池的高性能阴极具有很大的潜力.然而,低可达表面和剧烈的体积膨胀限制了其整体性能和实际应用.为此,采用相工程策略结合空心结构设计,调控OH−在电极表面的吸附/脱附,能显著提高电极的整体电化学性能.本研究首次利用Se@C纳米棒模板,通过原位硒化过程可控合成了一系列碳纳米管(CNT)负载的镍硒化物,包括立方型NiSe_(2)NiSe_(2)/Ni_(0.85)Se复合材料、六方型Ni_(0.85)Se.优化后的NiSe_(2)/Ni_(0.85)Se/CNT复合材料具有比表面积大、孔隙率高、碳骨架空心等优点,具有616Cg^(−1)的高比容量、优良的倍率性能和稳定的循环寿命.通过一系列的非原位表征和DFT计算,深入研究了其内部的法拉第机制.结果表明,所制备的Ni//Zn电池在3485 W kg^(−1)时具有311.4 W h kg^(−1)的高能量密度和较长的循环寿命.本研究为硒化镍基电极材料的设计提供了一种巧妙的策略,且深入研究了其在碱性锌电池中的法拉第机理.展开更多
基金the NSFC(Grant Nos.21875285 and 21805155)Taishan Scholars Program(ts201511019)+1 种基金Key Research and Development Projects of Shandong Province(2019JZZY010331)the Fundamental Research Funds for the Central Universities(19CX05001A).
文摘Constructing heterojunction is a promising way to improve the charge transfer efficiency and can thus promote the electrochemical properties.Herein,a facile and effective epitaxial-like growth strategy is applied to NiSe2 nano-octahe-dra to fabricate the NiSe2-(100)/Ni(OH)2-(110)heterojunction.The heterojunction composite and Ni(OH)2(performing high electrochemical activity)is ideal high-rate battery-type supercapacitor electrode.The NiSe2/Ni(OH)2 electrode exhibits a high specific capacity of 909 C g^-1 at 1 A g^-1 and 597 C g^-1 at 20 A g^-1.The assembled asymmetric supercapacitor composed of the NiSe2/Ni(OH)2 cathode and p-phenylenediamine-functional reduced graphene oxide anode achieves an ultrahigh specific capacity of 303 C g^-1 at 1 A g^-1 and a superior energy density of 76.1 Wh kg^-1 at 906 W kg^-1,as well as an outstanding cycling stability of 82%retention for 8000 cycles at 10 A g^-1.To the best of our knowledge,this is the first example of NiSe2/Ni(OH)2 heterojunction exhibiting such remarkable supercapacitor performance.This work not only provides a promising candidate for next-generation energy storage device but also offers a possible universal strategy to fabricate metal selenides/metal hydroxides heterojunctions.
基金supported by the National Natural Science Foundation of China(21875285,22001265)Taishan Scholar Foundation(ts201511019)+2 种基金the Key Research and Development Projects of Shandong Province(2019JZZY010331)the Fundamental Research Funds for the Central Universities(19CX05001A)the Natural Science Foundation of Shandong Province(ZR2020QB028)。
文摘金属硫系化合物作为水相锌电池的高性能阴极具有很大的潜力.然而,低可达表面和剧烈的体积膨胀限制了其整体性能和实际应用.为此,采用相工程策略结合空心结构设计,调控OH−在电极表面的吸附/脱附,能显著提高电极的整体电化学性能.本研究首次利用Se@C纳米棒模板,通过原位硒化过程可控合成了一系列碳纳米管(CNT)负载的镍硒化物,包括立方型NiSe_(2)NiSe_(2)/Ni_(0.85)Se复合材料、六方型Ni_(0.85)Se.优化后的NiSe_(2)/Ni_(0.85)Se/CNT复合材料具有比表面积大、孔隙率高、碳骨架空心等优点,具有616Cg^(−1)的高比容量、优良的倍率性能和稳定的循环寿命.通过一系列的非原位表征和DFT计算,深入研究了其内部的法拉第机制.结果表明,所制备的Ni//Zn电池在3485 W kg^(−1)时具有311.4 W h kg^(−1)的高能量密度和较长的循环寿命.本研究为硒化镍基电极材料的设计提供了一种巧妙的策略,且深入研究了其在碱性锌电池中的法拉第机理.
