Passivation and Corrosion Abilities of Lithium Salt Electrolytes

Passivation and Corrosion Abilities of Lithium Salt Electrolytes 

Electrolytes in energy storage devices react not only with the active material, such as activated carbon in double layer capacitors (DLCs) or carbon and metal oxides in Uthium-ion batteries on the anode and cathode respectively. The active material is fixed on metal foils that serve as current collector. So the foil is also in contact with the electrolyte and undergoes electrochemical reactions. 

In energy storage investigations, corrosion and protection of aluminum are of special interest In Uthium-ion batteries, the active material, for example, a transition metal compound (IiM02, M = V, Cr, Fe, Co, Ni.) [279-283], is fixed on aluminum, forming the cathode. Due to its high conductance, high available 

If passivation did not take place on the A1 surface, electrolyte decomposition and A1 deletion would diminish the cell s capabihty and even destroy the whole cell. But film formation and therefore passivation of the A1 surface is highly dependent on the choice of lithium salt [285] or film-forming additives. Table 17.9 shows oxidation potentials Eq of several lithium salts at aluminum. 

The reason for the corrosivity of lithium salts Hke liOTf, LiTFSI, or liMe in organic solvents is the anion. The reduction products of the trifluoromethylsulfonyl anions undergo reactions with aluminum on the surface, the reaction products desorb from the surface, and the characteristic pit corrosion develops [293]. Naka-jima et al. [294] propose the following reactions for the dissolution of aluminum  

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