Interestingly your two questions point towards a trade off in battery design. Current research is adding more silicon to the batteries to increase energy densit

Interestingly your two questions point towards a trade off in battery design. Current research is adding more silicon to the batteries to increase energy density but doing so makes the battery degrade. https://phys.org/news/2019-01-tiny-silicon-particles-power-lithium.html https://phys.org/news/2019-01-tiny-silicon-particles-power-l... "Silicon shows promise for building much higher-capacity batteries because it's abundant and can absorb much more lithium than the graphite used in current lithium ion batteries. The problem is that silicon is prone to fracturing and breaking after numerous charge-and-discharge cycles, because it expands and contracts as it absorbs and releases lithium ions."