Answer to Question #177055 in General Chemistry for Geek

Question

When a lithium ion battery is being CHARGED (i.e. not in use or "discharged"), the flow of electrons and Li+ ions is

a. from graphite electrode to cobalt oxide electrode

b. from cobalt oxide electrode to graphite electrode

c. Li+ towards cobalt oxide electrode but e- towards graphite electrode

d. Li+ towards graphite electrode but e- towards cobalt oxide electrode

Answer 1

The answer is b.

Li+ ions and electrons move from the cobalt oxide (positively charged) to the graphite (negatively charged).

When discharged, the Li+ ions are in the positive electrode material (cobalt oxide). Thus, the positive electrode becomes the source of Li+ ions necessary for the conversion of electrical energy into chemical energy (charging). To allow Li+ ions to migrate from the postive electrode to the negative electrode, the electrolyte (the separator) is enriched with Li+ ions.

Electrons also migrate from the positive electrode (oxidation) to the negative electrode (reduction) via an external conductor.