Failure of graphite electrodes

In the case of solutions based on a solvent such as propylene carbonate (PC), the failure of graphite electrodes is attributed by some researches to the exfoliation of the graphite particles due to cointercalation of PC molecules with the Li ions.14,22 The difference between ethylene carbonate (EC) and PC in this respect may, according to this approach, be attributed to the higher ability of PC molecules to solvate Li ions.23 Hence, cointercalation of PC molecules takes place because their desolvation from Li ions, which migrate from solution phase to the intercalation sites in the graphite,... 

On the Proposed Scenarios of Stabilization and Failure of Graphite Electrodes... 

From the above discussion, it is clear that the stabilization or failure of graphite electrodes depends on a delicate balance between passivation phenomena (due to the formation of highly cohesive and adhesive surface films) and a buildup of internal pressure due to the reduction of solution species inside crevices in the graphite particles. This delicate balance can be attenuated by both solution composition (EC-DMC vs. EC-PC or PC, etc.) and the morphology of the graphite particles (i.e. the structure of the edge planes and the presence of crevices). 

There is an ongoing interest in the study of failure mechanisms of graphite electrodes. It is very important to understand the source of the... 

Figure 1 provides several electrochemical windows of important, relevant processes, including the reduction of alkyl carbonates, ethers, Li insertion into graphite, and Li metal deposition. Recent studies revealed two major failure mechanisms of graphite electrodes in repeated Li insertion/ deinsertion processes 21... 

Aurbach, D. Levi, M. D. Levi, E. Schechter, A. Failure tuid Stabilization Mechanisms of Graphite Electrodes, J. Phys. Chem. B 1997,101,2195—2206. 

The irreversible capacity of graphite electrodes depends not only on the solution composition, but also on the structural and morphological parameters of the particles. In solutions in which there are no specific failure mechanisms of graphite electrodes (i.e., highly reversible behavior is observed, as in EC-DEC, EC-DMC, EC-EMC solutions, etc.), the irreversible capacity depends on the average particle s surface area [129]. 

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