Revealing the intrinsic effects of introduced carbon nanotubes for Bi2O3 energy storage materials

A lot of works have revealed that the introduction of Carbon nanotubes (CNTs) into oxide-based electrode materials is an efficient strategy to improve their energy storage performance. In this work, we firstly demonstrated the intrinsic effects of introduced CNTs for bismuth oxide (Bi2O3) electrode materials, including the physical, chemical and energy storage performance. Our results revealed that the optimal value of introduced CNTs into Bi2O3 is 1.5% (in weight ratio), which demonstrated a specific capacitance of 1012 C g−1 at 1 A g−1, about 1.52 times higher than the pristine Bi2O3. The obtained optimal energy storage performance by introduced CNTs can be explained by; 1) the introduced CNTs were helpful to reduce the average particle size of Bi2O3 powder, here the particle size was greatly reduced from 363 nm to 112 nm; 2) the small Bi2O3 particle with the introduced CNTs demonstrated more than 1.97 times enhancement of specific surface area; 3) the total conductivity of the obtained composite electrode was greatly enhanced by 320.31 times and, 4) however, due to the lower theoretical capacity of CNTs, the total specific capacitance of composite electrode showed a significant reduction by introducing excess CNTs. We believe that this work provides a strong support to guide the introduction of CNTs into Bi2O3-based energy storage materials for optimizing electrochemical performance.