Parameter Evaluation of Printed Primary Zn/MnO 2 -Batteries with Nonwoven and Hydrogel Separator

Potentially important parameters of printed flexible batteries based on the primary zinc -manganese dioxide (Zn/MnO 2 ) system were investigated using a fractional factorial design of experiments (DOE). A novel hydrogel electrolyte made of lactic acid and cornstarch proved functionality. Using this kind of hydrogel, it is important to impede unwanted sidereactions with the zinc electrode. Accurate control of the electrode mass is absolutely necessary, since the mass of deposited MnO 2 and the mass ratio of MnO 2 :Zn determines the capacity of the cells. With optimised parameter settings the capacity of printed cells was increased to over 100 mAh, which is equivalent to an area- related specific capacity of about 7.3 mAh/cm 2 . This is within the range of the commercially available button cells, which were supplied with the same discharge conditions between 125 and 155 mAh. By means of electrochemical impedance spectroscopy (EIS) the cells were examined immediately after assembly. Within three hours the cell could be identified as in principle working or defect. As such, precious measurement time can be saved by selecting promising cells prior to characterisation.