Sustainable Gel Electrolyte Containing Pyrazole as Corrosion Inhibitor and Dendrite Suppressor for Aqueous Zn/LiMn₂O₄ Battery

Abstract

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.

3D zinc@carbon fiber composite framework anode for aqueous Zn–MnO2 batteries

“…Primary Zn dendrites can puncture the diaphragm, causing short circuits. Lots of approaches have been proposed to optimize these problems such as adding additives in the electrolyte to modify the deposition behavior, 21,22 coating a new protective layer on the surface of Zn metal 23,24 or using Zn-alloy [25][26][27] to improve conductivity and anti-corrosion property. Unfortunately, most of the improvements are either expensive or hard to maintain a long lifespan during cell cycling.…”

Latest Advances in High-Voltage and High-Energy-Density Aqueous Rechargeable Batteries

“…Due to the limitation of the electrochemical stability window, the formation of zinc dendrites, and the corrosion of the negative zinc electrode, modification of the electrolyte is another effective way to improve the electrochemical performance of aqueous Zn/LiMn 2 O 4 hybrid batteries. Many additives, including thiourea (TU) [40], SiO 2 [41], cyclodextrin (CD) [42], and fumed silica (FS) [43], were introduced into the electrolyte to improve the electrochemical performance of hybrid batteries. Although there are some improvements, the effects are still not satisfactory and further improvement is needed.…”

Strategies to Enhance Corrosion Resistance of Zn Electrodes for Next Generation Batteries

“…In addition, inhibitors that can be compatible to new electrolytes have also been studied. Chen and coworkers developed a mildly acidic electrolyte containing 5% fumed silica (FS) for Zn-LiMn 2 O 4 battery (Hoang et al, 2017;Xiong et al, 2018;Mitha et al, 2019). This electrolyte reduced the dendrite growth of Zn electrode but would increase the corrosion rate.…”