DICK POUNTAIN
Phone out of battery? In the future, you’ll dip it into your tea.
Batteries, dontcha just hate them? For the ten-thousandth time, I forgot to plug in my phone last night, so when I grabbed it to go out it was dead and I had to leave it behind on charge. My HTC phone’s battery will last over two days if I turn off various transceivers, but life’s too short. And phones are only the worst example, to the extent that I now find myself trying to avoid buying gadgets that require batteries. I have self-winding wristwatches, but I’m too sedentary to keep them wound and they sometimes stop at midnight on Sunday. I don’t care for smartwatches, but I did return to quartz with a Bauhaus-style Braun BN0024, with a card-full of those irritating button batteries bought off Amazon that may last out my remaining years.
It isn’t just personal gadgets that suffer from the inadequacy of present batteries: witness the problems airliner manufacturers have had in recent years with in-flight fires caused by the use of lithium-ion cells. It’s all about energy density: we demand more power while away from home, and that means deploying batteries that rely on ever more energetic chemistries, which begin to approach the status of explosives. I'm sure it isn’t only me who suffers a frisson of anxiety when I feel how hot my almost-discharged tablet sometimes becomes.
New battery technologies look likely in the future, perhaps non-chemical ones that store power drawn from the mains into hyper-capacitors made using graphenes. Energy is still energy, but such ideas raise the possibility of lowering energy density by spreading charge over larger volumes – for example, by building the storage medium into the casing of a gadget using graphene/ plastic composites. Maybe hyper-capacitors will trickle-charge themselves on the move using kinetic, solar and induction sources.
Nature found its own solution to this problem, from which we may be able to learn something, and it turns out that distributing the load is it. Nature had an unfair advantage in that its development department has employed every living creature that's ever existed, working on the task for around 4 billion years. Intriguingly, though, that colossal effort came up with a single solution very early on that is still repeated almost everywhere: the mitochondrion.
Nearly all the cells of living things above the level of bacteria contain both a nucleus and a number of mitochondria, the cell’s battery chargers that power all its processes by burning glucose to create adenosine triphosphate, the cellular energy fuel.
Mitochondria contain their own DNA, separate from that in the nucleus, leading evolutionary biologists to postulate that billions of years ago they were independent single-celled creatures who “came in from the cold” and became symbiotic components of all other cells. Some cells – red blood cells, for instance – contain no mitochondria; others, such as liver cells, contain thousands. Every cell is its own battery, constantly recharged by consuming oxygen from the air you breathe and glucose from the food you eat to drive these self-replicating chargers.
So has nature also solved the problems of limited battery lifespan and loss of efficiency (the “memory effect”)? No, it hasn’t, which is why we all die. However, longevity research is as popular among the Silicon Valley billionaire digerati as are driverless cars and Mars colonies, and recent years have seen advances in our understanding of mitochondrial ageing. Enzymes called sirtuins stimulate production of new mitochondria and maintain existing ones, while each cell’s nucleus continually sends “watchdog” signals to its mitochondria to keep them switched on. The sirtuin SIRT1 is crucial to this signalling, and in turn requires nicotinamide adenine dinucleotide (NAD) for its effect, but NAD levels tend to fall with age. Many of the tricks shown to slow ageing in lab animals – calorie-restricted diets, dietary components such as resveratrol and pterostilbene – may work by encouraging the production of NAD.
Now imagine millions of synthetic mitochondria, made from silicon and graphene by nano-engineering, charging a hyper-capacitor shell by burning a carbohydrate fuel with atmospheric oxygen. Yes, you'll simply use your phone to stir your tea, with at least one sugar. I await thanks from the sugar industry.
I’m sure it isn’t only me who suffers a frisson of anxiety when I feel how hot my almost-discharged tablet sometimes becomes