Enhanced electrochemical supercapacitors from the metal silicates (Zn, Mn, Ni and Co) by multi-step treatment of natural green algaes

Abstract Metal-silicates (Zn, Mn, Ni and Co) were synthesized from natural green algaes ( GAs ) as supercapacitor electrodes. In this study, multi-step treatment with two kinds of porogenes was used to produce larger specific surface area and more abundant hierarchical pores. Firstly, GAs was treated with 1.0 M NaCl solution to prepare large pores. Secondly, metal-silicates were synthesized by the GAs using hydrothermal reaction. Lastly, the as-synthesized samples were soaked in 3.0 M NaOH solution to obtain the products (m-C-MSi, M= Zn, Mn, Ni and Co). Compared with the composites without multi-step treatment, the synthetic materials in this research possess excellent electrochemical properties both as electrodes and as HSCs . This work proved that the multi-step treatment with porogenes is an effective method to enhance the electrochemical performance of the metal-silicate supercapacitors.