Inside a lithium ion battery
Imagine two slices of bread. Each loaf is an electrode: a cathode on the left and an anode on the right. Let's assume that the cathode is made of thin sheets of nickel, manganese and cobalt (NMC) -- one of the best in its class -- and the anode is made of graphite, which is essentially made up of layered sheets or sheets of carbon atoms.
In the discharge state, that is, after the energy is exhausted, the NMC bread has lithium ions sandwiched between each slice. When the battery is charged, each lithium ion is extracted from between the sheets and forced through a liquid electrolyte. The separator acts as a checkpoint, ensuring that only lithium ions pass through the graphite layer. When the battery is fully charged, the cathode layer of the battery is not left with lithium ions, but neatly sandwiched between layers of graphite. When the battery is drained, the lithium ions return to the cathode until there are no lithium ions left in the anode. The battery needs to be recharged.
The battery's energy capacity basically depends on how fast this process happens. But increasing speed is not easy. Removing lithium ions from the cathode bread too quickly can cause the slices to defect and eventually break. That's one reason why the longer we use smartphones, laptops or electric cars, the worse their battery life gets. Each charge and discharge weakens the bread.

Many companies are trying to solve this problem. One idea is to replace layered electrodes with materials that are structurally stronger. For example, Leclanch_, a 100-year-old Swiss battery company, is working on a technology that uses lithium iron phosphate (LFP), which has a "olivine" structure, as the cathode, and lithium titanate (LTO), which has a "spinel" structure, as the anode. These structures are better at handling the flow of lithium ions into and out of materials.

Leclanche currently uses batteries in automated warehouse forklifts that can be charged to 100% in 9 minutes. By comparison, the best Tesla superchargers can charge a Tesla car's battery to about 50 percent in 10 minutes. Leclanche is also deploying its batteries in the UK for fast-charging electric cars. These batteries sit at charging stations and slowly absorb small amounts of power from the grid over long periods of time until they are fully charged. Then, when the car is parked, the docking station battery quickly recharges the car battery. When the bus left, the station's batteries began to charge again.
Efforts like Leclanche's show that it is possible to tinker with battery chemicals to boost their power. Still, no one has built a battery powerful enough to quickly release the energy needed for commercial aircraft to beat gravity. Start-ups are looking to build small planes (which can seat up to 12 people) that can use relatively low-power, intensive batteries or electric hybrid aircraft, where jet fuel is difficult to lift and batteries taxi.

But there are no companies investing in this near-commercial sector. Moreover, the technological leap required for an all-electric commercial aircraft could take decades, says VenkatViswanathan, a battery expert at Carnegie Mellon university.

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