皱褶表面介孔镍钴硫化物微球的制备及其超电性能

One-step Hydrothermal Synthesis of Mesoporous Ruffle-like Sulfide Microspheres for Supercapacitors

通过一步水热法分别合成了α-Ni S、Co_3S_4和Co Ni_2S_4纳米介孔电极材料,并研究了其电化学性能。X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究表明,介孔硫化物是由单相纳米颗粒堆叠组装而成,其中二元系的Co Ni_2S_4由纳米片自组装形成了具有皱褶表面的微球形貌。电化学性能研究表明,二元系的Co Ni_2S_4比α-Ni S、C o_3S_4具有更高的比电容、更佳的倍率特性和优异的循环稳定性。在扫描速率为5 m V/s时,Co Ni_2S_4材料在6 mol/L KOH电解液中比电容高达1678.3 F/g,优于α-Ni S(787.4 F/g)和Co_3S_4(1532.7 F/g),在扫描速率从5 m V/s增加到100 m V/s时,其电容保持率为45.8%,比α-Ni S(30.2%)和Co_3S_4(29.3%)高出约15%。在15A/g的电流密度下,经过900次循环充-放电后,二元系的Co Ni_2S_4的电容仍保持在96.3%,库伦效率保持在94.3%左右,说明镍钴双金属硫化物具有优异的循环稳定性能和充放电可逆性。

Mesoporous α-NiS, Co3S4 and CoNi2S4 electrode materials were synthesized by a simple one-step hydrothermal method, and their electrochemical properties were investigated. X-ray diffraction and electron microscopy results show that as-obtained mesoporous sulfide electrode materials are assembled by single-phase sulfide nanoparticles and the CoNi2S4 electrode materials have the unique structure of ruffle-like microspheres consisting of 2D nanoplates. The binary CoNi2S4 electrode exhibits much higher specific capacitance of 1678.3 F/g than that of either Co3S4（1532.7 F/g） or α-NiS（787.4 F/g） in 6 mol/L KOH at a scan rate of 5 mV/s, and shows excellent capability retention of 45.8% from 5 mV/s to 100 mV/s, which is ~15% higher than that of α-NiS and Co3S4. The excellent cycling stability of binary CoNi2S4 electrode is achieved with 96.3% of the initial capacitance over 900 consecutive cycles at 15 A/g. Moreover, the columbic efficiency consistently remains above 94.3% within 900 cycles. The fine specific capacitance and good cycling stability demonstrate that the mesoporous CoNi2S4 electrode has potential applications in supercapacitors.