ORIGINAL PAPER The effect of dimensional ratio and proportion of micron-nanoparticles on discharge performance of silver (ІІ) oxide cathode Mostafa Najafi 1 & Amin Abedini 1 Received: 2 December 2018 /Revised: 12 January 2019 /Accepted: 17 January 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract The silver (П) oxide (AgO) powders as cathode material in Ag-based battery were synthesized with different dimensional ratios (DRs) and characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The SEM results indicated that AgO particles were slice in morphology. Also, the particle sizes were classified in three categories, including nanoscale with DR = 1 to 3, submicron/μm mixture with DR = 3 to 20 and nanoscale/ submicron/μm mixture with DR = 3 to 15. The electrochemical performance of AgO particles as cathode active materials was investigated. The results of galvanostatic discharge at 80 mA/cm 2 indicated that the highest capacity (400 mAh/g) and lowest potential drop were obtained for submicron/μm mixture of AgO particles. The best discharge performance at high current density (600 mA/cm 2 ) was obtained for the cathodes prepared with high proportion of micron AgO particles. Keywords Silver (П) oxide . Size controlled . Galvanostatic discharge . Delivered capacity . Cathode strength . Dimensional ratio Introduction Silver (П) oxide (AgO) is extensively used as the cathode material for power sources in numerous military and commer- cial applications [1–3]. The high voltage and capacity of AgO make it very attractive as cathode materials in silver-based batteries [4–6]. Electrochemical [7–9] and chemical methods [10–14] are two general routes for synthesis of AgO particles. The electrochemical methods suffer from high impurities such as Ag 2 O, Ag, and Ag 2 CO 3 in final product. These impurities cause serious problem during cathode storage [15]. Unlike the electrochemical methods, pure AgO particles can be achieved by chemical methods. Among these, the alkaline oxidation method by K 2 S 2 O 8 [13] is an efficient and superior method for the synthesis of AgO particles. The benefits of the alkaline oxidation method are the availability, simplicity of equipment, controllable condition of synthesis, and the absence of com- plex byproducts. The AgO particles have been investigated by several re- search groups as a cathode active material. The discharge ca- pacity, strength, and potential drop are important studied fea- tures in these investigations [16–20]. The synthesis of AgO nanoparticles (nanoscale only in the thickness) by alkaline oxidation method in presence of NaClO was reported by Pan et al. [10]. They showed that prepared electrodes of AgO nanoparticles have good electrochemical characteristics at high current density. Smith and Brown investigated the discharge of AgO electrodes in low current density. They showed that the voltage and capacity were affected by accel- erated aging at high temperature [18]. The discharge profile of AgO cathode usually has two pla- teaus. The plateau 1 is for reduction of AgO to Ag 2 O. Transition from plateau 1 to plateau 2 occurs before complete reduction of AgO. At plateau 2, both AgO and Ag 2 O are discharged simul- taneously and a layer of silver (І) oxide (Ag 2 O) covers the surface of AgO [16–18]. Liu et al. investigated the effect of mixing of micron-sized AgO and nanophase Ag 2 O particles on discharge performance. Under the same discharge condition, the relative amount of Ag 2 O nanophase in the active material determines the length of the plateau of discharge [19]. The control electrochemical properties of active materials by tuning chemical composition and morphological Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11581-019-02880-2) contains supplementary material, which is available to authorized users. * Mostafa Najafi mnajafi@ihu.ac.ir 1 Department of Chemistry, Faculty of Science, Imam Hossein University, Tehran 16597, Iran Ionics https://doi.org/10.1007/s11581-019-02880-2