I really feel the tech around batteries needs particular focus, as the one thing computing technology seems to lag on is battery life - I dream of a time where I can charge my laptop once a year and not have to worry about it otherwise.
Perhaps 3D printing of batteries will offer easier iteration on new ideas?
Once a typical Li-ion battery is a few years old it might as well be worthless, it will hold only a fraction of the original charge it could when it was new and that amount will continue to drop over time. If we could build batteries with even 80% of the storage density of Li-ion but would retain 90% of that capacity over 10 years I'd be pretty happy.
Note: don't go cheap by buying Chinese crap for battery chargers, especially Li chemistries. Best case: works as advertised. Worst case: electrocution or house goes up in flames.