Hoang Tuan K A, Doan The Nam Long, Cho Julie Hyeonjoo, Su Jane Ying Jun, Lee Christine, Lu Changyu, Chen P
Department of Chemical Engineering and Waterloo Institute of Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
ChemSusChem. 2017 Jul 10;10(13):2816-2822. doi: 10.1002/cssc.201700441. Epub 2017 Jun 5.
The Zn anode in secondary aqueous batteries suffers from dendrite formation and corrosion. In this work, dendrite formation was suppressed by using a simple but new gel electrolyte containing fumed silica and an additive. The dendrite suppression was evidenced by chronoamperometry and ex situ scanning electron microscopy examinations. Pyrazole was implemented as the additive in the electrolyte. It was found that the presence of 0.2 wt % pyrazole in the electrolyte helped minimize both corrosion and dendrite formation. The Zn/LiMn O battery using pyrazole-containing gel electrolytes exhibited high cyclability up to 85 % capacity retention after 500 charge-discharge cycles at 4C. This was 8 % higher than the performance of the reference battery (using aqueous electrolyte containing 2 m Li SO and 1 m ZnSO ). Furthermore, self-discharge of the battery with the pyrazole-containing gel electrolyte was suppressed, as evidenced by an open-circuit voltage loss that was 20 % lower than for the reference battery after 24 h monitoring. Float-charge current density under constant voltage (2.1 V) also significantly decreased from approximately 8.0 to 3-6 μA.
二次水系电池中的锌阳极会出现枝晶形成和腐蚀问题。在这项工作中，通过使用一种含有气相二氧化硅和添加剂的简单但新型的凝胶电解质来抑制枝晶形成。通过计时电流法和非原位扫描电子显微镜检查证明了枝晶抑制效果。吡唑被用作电解质中的添加剂。结果发现，电解质中存在0.2 wt%的吡唑有助于使腐蚀和枝晶形成都最小化。使用含吡唑凝胶电解质的锌/锂锰氧化物电池在4C下经过500次充放电循环后表现出高达85%的容量保持率，具有高循环稳定性。这比参比电池（使用含有2 m硫酸锂和1 m硫酸锌的水系电解质）的性能高8%。此外，含吡唑凝胶电解质的电池自放电得到抑制，在24小时监测后开路电压损失比参比电池低20%就证明了这一点。恒压（2.1 V）下的浮充电流密度也从约8.0显著降低至3 - 6 μA。
