Size effect on interfacial pseudocapacitive contributions to lithium-ion storage in microscale carbon/TiO2 nanosheet composite

The research on pseudocapacitive characteristics is mostly focused on the nano-or submicron-scale metal-oxide electrode materials. However, the studies on related properties are still rare in the micro-scale materials. Electrode materials with a microscale particle size can exhibit higher tap density and lower specific surface areas, which are more conducive to commercial applications. Therefore, here we present a study about the effects of particle size on interfacial pseudocapacitive contributions to lithium-ion storage and the internal dynamics associated with the interfacial ion diffusions in two-dimensional microscale carbon/TiO2 nanosheet superlattice composites. The results reveal the initial particle size of the layered material exhibits significant effects on the kinetics of the pseudocapacitive redox reactions that lead to different rate behaviors. The higher reversible capacity will be achieved with the smaller particle size for the microscale-layered carbon/TiO2 nanosheets. A specific capacity of 512.5 mAh/g and a high pseudocapacitive reaction at a current of 0.1 A/g are achieved for carbon/TiO2 with a particle size of 4.3 mm. The excellent electrochemical properties of the microscale-layered carbon/TiO2 are attributed to the increase in the interfacial pseudocapacitive contribution, and the decrease in the ion diffusion path resulted from the decrease in the particle sizes.(c) 2022 Elsevier Ltd. All rights reserved.