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The lithium-ion battery is a secondary cell that is now widely used in portable electronic devices: In these batteries, lithium ions, Li^+, move through a special non-aqueous electrolyte between the two electrodes - VCE - SSCE Chemistry - Question 8 - 2016 - Paper 1
Question 8
The lithium-ion battery is a secondary cell that is now widely used in portable electronic devices: In these batteries, lithium ions, Li^+, move through a special no... show full transcript
Worked Solution & Example Answer:The lithium-ion battery is a secondary cell that is now widely used in portable electronic devices: In these batteries, lithium ions, Li^+, move through a special non-aqueous electrolyte between the two electrodes - VCE - SSCE Chemistry - Question 8 - 2016 - Paper 1
Step 1
During discharge, what is the polarity of the graphite electrode?
Answer
During the discharge of a lithium-ion battery, the graphite electrode acts as the anode, which carries a negative charge. This happens because lithium ions, Li^+, move from the anode (graphite) to the cathode (LiCoO2) during discharge.
Step 2
Step 3
Explain why and justify your answer with the use of appropriate equations.
Answer
Lithium metal must not be in contact with water because it reacts vigorously with water, potentially leading to a fire or explosion. The reaction can be represented as:
2Li_s + 2H_2O_{(l)} \rightarrow 2LiOH_{(aq)} + H_2_{(g)}
Hydrogen gas is produced as a byproduct, which is highly flammable. Therefore, to prevent any dangerous reactions, lithium metal should be kept dry.