Effect of fine layer structure on electrochemistry properties

Abstract In this work, we have mainly investigated the electrochemical properties of Bi 2 SiO 5 and Bi 2 O 2 CO 3 . They have the different layer structures and the areal capacitance (10.1 mF cm − 2 ) of Bi 2 O 2 CO 3 electrode is 2.9 times higher than that (2.6 mF cm − 2 ) of Bi 2 SiO 5 one at 0.1 mA cm − 2 . After 4000 cycles, 84% and 81% capacitances are retained for Bi 2 O 2 CO 3 and Bi 2 SiO 5 electrodes, respectively. Because Bi 2 O 2 CO 3 has a lower BET area (3.634 m 2  g − 1 ) and a higher electrical resistance (5.231 Ω cm 2 ) than Bi 2 SiO 5 (35.13 m 2  g − 1 , 2.022 Ω cm 2 ), their different electrochemical properties have been mainly attributed to the different fine layer structures. For Bi 2 O 2 CO 3 , the anion layers and cation layers are completely separated and the unobstructed passageways form, which would favour to get in and out for ions and improve the capacitance. For Bi 2 SiO 5 , the newly-formed Bi O Si bonds can improve conductivity, but there is no passageway between the anion layers and cation layers, which does not favour for the getting in and out of ions. This study demonstrates that fine layer structure has a significant influence on the electrochemical properties.