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 non... 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?
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Answer
During discharge, the graphite electrode acts as the anode, therefore, it has a negative polarity. This is because electrons are produced at the anode and flow toward the cathode.
Step 2
Write the half-equation for the reaction that occurs at the cathode of a lithium-ion battery when it is recharged.
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Answer
The half-equation for the reaction at the cathode during the recharging process is:
ightarrow LiC_6$$
Step 3
In a lithium-ion battery, lithium metal must not be in contact with water. Explain why and justify your answer with the use of appropriate equations.
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Lithium is a highly reactive metal that readily reacts with water. The reaction can be represented as:
ightarrow 2LiOH_{(aq)} + H_2(g)$$
This reaction produces lithium hydroxide and hydrogen gas, the latter being flammable and posing a significant safety hazard. Additionally, the generation of heat during the reaction can lead to further complications such as fires or explosions. Therefore, to minimize risks, lithium metal must not be allowed to contact water.