All batteries have four components: two electrodes (anode and cathode), a liquid electrolyte that helps ions move between the electrodes, and a separator to keep the electrodes from coming in direct contact with each other and preventing fires. When a battery is charged, ions flow from the cathode to the anode. When it’s discharged, the ions reverse course.
A battery is judged by how much energy it packs. That key factor is intimately linked to the battery’s charging speed, the number of charge-discharge cycles it can sustain, and safety. Increased energy density can also make it more fire prone. Faster recharge speed can result in fewer life cycles.
Ultimately, price reigns supreme. That’s determined by how much energy the battery can store, the materials used to make it and the thickness of electrode coatings that can be deployed without harming performance. The lower the cost, the cheaper the electric car.
British scientist John Goodenough found that cathodes made entirely of cobalt were safer and stored more energy. The discovery won him the Nobel Prize in chemistry in 2019. Then Moroccan scientist Rachid Yazami found that using graphite, a form of carbon, as the anode made a lithium-ion battery much more stable and thus helped it last longer. Finally, Keizaburo Tozawa, head of Sony’s battery division in the 1990s, put all these inventions together to create the first commercial lithium-ion battery.
Even though cobalt is an expensive metal, it remained affordable for small batteries inside early laptops and mobile phones. But once lithium-ion batteries started moving into electric vehicles, chemists looked to introduce cheaper metals, such as nickel, manganese and even iron.
Alternative metals have to be carefully evaluated. If a cheap metal means disproportionately worse battery performance, it won’t do. Through millions of experiments, three cathode chemistries have come to dominate the market: nickel manganese cobalt oxides (NMC), nickel cobalt aluminum oxides (NCA) and lithium iron phosphate (LFP).
Into the Solid-State Future
If solid-state batteries come to market in the latter half of this decade, as expected, they are likely to represent a big leap in battery performance, extending EV range by as much as 50% and cutting down charging times to as little as 15 minutes.
Read more at: https://www.bloomberg.com/graphics/2021-inside-lithium-ion-batteries/