Evaluate using graphene in batteries (6 marks)

Question: A scientist claims: 'Graphene will replace all current materials used in batteries and touchscreens within ten years.' Evaluate this claim, using your knowledge of the structure and properties of graphene. [6]

Mark scheme (6 marks): Indicative content — credit a balanced answer leading to a justified conclusion.

For (up to 4):

• Graphene is an excellent electrical conductor because of one delocalised electron per atom (1)
• It is extremely strong per unit mass — strong covalent C–C bonds in a 2D lattice (1)
• Flexible and transparent because it is only one atom thick — ideal for bendable touchscreens (1)
• High surface area to volume ratio — useful for electrodes that store charge (1)

Against (up to 3):

• Difficult and expensive to manufacture in large, defect-free sheets (1)
• Existing materials (e.g. lithium compounds, ITO) are well-developed and cheap (1)
• Long-term safety / environmental impact of nanomaterials not fully known (1)

Conclusion (1):

• A justified judgement, e.g. 'Graphene will likely replace some materials (e.g. ITO in flexible touchscreens) within ten years, but full replacement of battery chemistries is unlikely until cheap, large-scale manufacture is achieved.' (1)

Levels guidance: 5–6 = balanced argument, correct science, justified conclusion. 3–4 = some balance, mostly correct science. 1–2 = one-sided or limited science.