Carbon materials have attracted extensive attention for ion battery anode because of the merits of their low cost, high electric conductivity, and thermal and chemical stability, etc. By tuning the particle size, morphology, surface area and porosity, some carbon anodes exhibit capacities above the theoretical value predicted based on hybrid ion storage mechanisms of insertion and adsorption. However, in most cases, it is hard to simultaneously maintain the high specific reversible capacity and cyclic stability. In addition, in contrast to conventional observations of loss upon cycling, capacity increases are sometimes observed, especially when porous carbons are used as lithium-ion battery anode. Here, we will introduce our current understanding of the mechanism on cyclic stability in carbon-based anodes for ion batteries. We will also discuss how the changes in the carbon structure can induce capacity enhancement upon cycling. These works give some insights into the mechanism of reversible ion storage of carbon-based anodes.
The mechanism on cyclic stability in carbon anode materials for ion batteries is studied. The capacity fading can be results from the irreversible decomposition of electrolyte and the irreversible trapping of ions within active sites with high adsorption energy. The capacity increase can be ascribed to the stepwise diffusion of ions inside the defect structure. Both capacity fading and capacity increase will harm the cyclic stability of carbon anode. Especially when the carbon anodes are applied in full-cells, the instable performance will result in serious capacity deterioration.

 

carbon,battery,anode