三维多孔Sn-Zn合金电极助力Zn的均匀沉积/剥离

Three-dimensional Porous Sn-Zn Alloy Towards Uniform Zn Plating/stripping

通过在化学镀构建的三维多孔铜上电沉积锡-锌(Sn-Zn)合金,构筑了孔径为5μm左右的三维多孔Sn-Zn合金电极(3D Sn-Zn),对其形貌、结构和性能进行了表征和测定.结果表明,该电极拥有高稳定性和适宜孔径的三维多孔结构,可降低局部电流密度,提供均匀的电场分布,缓解了由于锌的不均匀生长而造成的粗大枝晶;合金镀层中的Sn元素不仅可以增大析氢过电位,增强电极的防腐蚀性能,还可降低锌的形核势垒,为锌的沉积提供丰富的形核位点,促进锌在电极表面的均匀沉积,减少枝晶的形成.采用3D Sn-Zn电极组装的对称电池,在0.5 mA/cm^(2)下可稳定循环超过1200 h,电压滞后仅为21.3 mV;而采用锌片(2D Zn)组装的对称电池电压滞后达到了99.2 mV,且在循环300 h后开始出现剧烈的电压波动.使用3D Sn-Zn电极组装的全电池在1.8 A/g电流密度下可稳定循环2000次.

A unique three-dimensional(3D)porous Zn-Sn alloy electrode was conducted by electrodepositing Sn-Zn alloy on the 3D porous Cu formed from electroless plating to issue the dendrites growth and corrosion of Zn-based electrodes.The 3D porous structure with high stability and suitable pore size of about 5μm can reduce the local current density and provide uniform current distribution,thus induce uniform growth of zinc and reduce the formation of rough dendrites.The element Sn in this alloy can enhance the anticorrosion behavior through increasing the overpotential of hydrogen evolution,simultaneously induce uniform Zn deposition with less dendrite through decreasing the Zn nucleation energy barrier and providing abundant Zn nucleation sites.The symmetrical cell using two identical 3D porous Sn-Zn electrodes stably cycle for more than 1200 h with a small voltage hysteresis of 21.3 mV at 0.5 mA/cm^(2).In contrast,the symmetrical cell assembled using zinc foil(2D Zn)appears obvious voltage fluctuation after cycling for 300 h with a larger voltage hysteresis of 99.2 mV.The full cell is stable up to 2000 cycles at 1.8 A/g current.