Well, we also said that five years ago.
Mobile computing is great because it lets you play and work anywhere you want and anytime you want. And as mobile displays get bigger, processors run faster, and apps and services become more varied and powerful, the overall experience is also getting better - save for one area: battery life.
And that's because we haven't had a battery breakthrough in decades. Yes, small advances have been made over time, but all the radical ones, even those tested on lithium-ion batteries, have either failed or are still many years oﬀ. And if you think about it, this battery tech stagnation is a plague aﬀecting multiple industries, from mobile to auto. As a result, we've phones that can’t last a full day and electric cars with short ranges.
Most battery scientists today are focused on solving the limitations of lithium-ion, which are its long charging time, high volatility, and short lifespan. And the experiments are typically about replacing parts of the battery, like the anode and cathode ends with a diﬀerent material like carbon. Auto makers in particular are also exploring lithium-air battery tech, which plays with the reaction between lithium and oxygen to increase energy density.
For phones, the next big leap is likely going to be graphene batteries. In end 2017, Samsung Advanced Institute of Technology announced that it has developed a “graphene ball" to be used on both the anode protective layer and cathode materials in lithium-ion batteries. The resulting graphene-enhanced battery is said to have 45% more capacity and can charge 5x faster than a standard lithium-ion battery. It's unclear when we would see it debut on actual phones (the main problem with graphene is that it's diﬃcult and expensive to produce at scale), but a more recent rumor suggested that development has wrapped up, which gives hope that the next step is mass production and commercialization. Still, I'd be very surprised (but delighted) if the tech makes its way into the 2019 Galaxy S10.
The chance of graphene batteries being a thing is also higher because other big names are also looking into it, such as Huawei and Tesla. In fact, Huawei is already using graphene on its new Mate 20 X phone, though not for the battery but as a cooling material in lieu of more common materials such as copper.
REPLACING BATTERIES WITH SUPERCAPACITORS
There are camps that propose ditching electrochemical batteries for supercapacitors, because the latter are able to recharge in mere seconds, have a million charge-discharge cycles, and last up to 15 years. But that's unlikely to happen in the near term, at least for mobile devices.
The main reason is their lower stored energy per unit mass compared to traditional batteries, which means phones that use supercaps are going to be much thicker than phones that use rechargeable lithium-ion cells.