A search for new batteries
In pursuing technological advancement, humanity has always faced several fundamental problems, the most prevalent of which being energy. Humanity generated power with a variety of methods from natural gas to nuclear power plants. With the world continuously investing in more efficient ways to generate power, we are tasked with the problem of storing it.
The first battery was invented by Alessandro Volta in 1800, in an attempt to prove his conjecture that energy was generated by metal and not solely through “animal energy”. He arranged zinc, copper, and cloth soaked with salt water in such a way that the Zinc lost electrons in a process known as oxidation and the electrons flowed through the copper, ending up in the saltwater solution. This flow of electrons is electricity. If there was, for example, a lightbulb in between to mediate this flow of electrons, it would light up. Today, modern batteries don’t have pieces of salt water-soaked cloth but instead have dry cells, a non-liquid version of the electrolyte, which fulfill the same purpose. Batteries die when all the metal in a battery gets oxidized (1).
Rechargeable batteries essentially reverse this process, returning electrons to the metal from the dry cells. However, after thousands of charge cycles, even the batteries in your phone develop imperfections in the metal, causing them to die. Innovations in battery technology tend to find ways to slow this process down because batteries that develop fewer imperfections are longer -lasting and more efficient (1).
Lithium-ion batteries are on the cutting edge of technology today. Lithium-ion batteries have greater energy density than regular batteries and they last longer and charge faster. In these batteries, the anode, or the metal being oxidized, is lithium. Lithium wants to lose its atom in the 2s orbital which causes it to flow towards the cobalt in the cathode (the positively charged terminal). This cobalt has been oxidized by oxygen giving it a +4 state. Because opposite charges attract, the negatively charged particles move towards the positive end. Here there is a problem; because the positive cobalt is growing more and more negatively charged, the negatively charged lithium ions are less and less inclined to go towards the cobalt. The stronger the opposing charge, the stronger the attraction from the oppositely charged ion. This is solved by putting a substance in between these two ends called an electrolyte, which lets positive lithium ions migrate from the anode to the cathode but prevents negatively charged ions from doing the same. The cathode makes negative lithium ions more inclined to flow towards the Cobalt (3).
Where can science go beyond this? Researchers have made major strides toward a new technology called flow batteries. Flow batteries keep their electrolytes apart from the anode and cathode, mitigating most fire risks and increasing longevity over lithium-ion batteries. Moreover, batteries that use molten salt has been in discussion, where excess energy from the grid is used to heat salt, essentially turning electrical energy into thermal energy. Moreover, salt has been used as a replacement for Lithium, given that Sodium and Lithium are chemically similar. (2)
Overall, the problem of energy storage comes down to three things, scalability, energy density, and longevity. The hope is that the new up-and-coming companies find a way to create batteries that are not only long-lasting and energy-dense, but scalable enough to make them valuable players in the endless search for more efficient energy storage.
Sources:
- Jacobson, A. (2015, May 21). How batteries work. YouTube. Retrieved October 27, 2022, from https://www.youtube.com/watch?v=9OVtk6G2TnQ
- Xu, B. (2022, August 19). How salt and sand could replace lithium batteries. YouTube. Retrieved October 27, 2022, from https://www.youtube.com/watch?v=-vobMl5ldOs
- Tablante, T. (2019, March 4). How do lithium-ion batteries work? YouTube. Retrieved October 27, 2022, from https://www.youtube.com/watch?v=G5McJw4KkG8
Source for image: https://www.electrical4u.com/battery-working-principle-of-batteries/