Finally, the era of exploding gadgets may be coming to an end. A team of scientists and physicists at the Johns Hopkins Applied Physics Laboratory (APL) developed a new type of battery that can be soaked, shot, bent, cut, and even lit on fire and it still works fine. Could it be the foundation for an indestructible lithium-ion battery in the future?
Lithium-ion batteries shape the new world. These batteries are at the core of most rechargeable electronics, including laptops, cell phones, vapes, and electric cars. However, these power pouches depend on toxic, flammable materials, which means the smallest defect can cause the gadget to explode.
For the past five years, this team has worked hard on making a safer battery. After many trials, they’ve successfully developed a lithium battery that’s immune to failure. In 2017, the prototype of the battery was first unveiled, but at that time, it could only be shot, bent, cut, and soaked. In 2019, the researchers pushed it even further, turning it fireproof and boosting its voltages to levels similar to a commercial product.
Konstantinos Gerasopoulos, who is leading the research, says the secret to making an indestructible battery is all in the electrolyte. Electrolytes are conductive chemicals that carry and hold charge between the negative and positive ends of a battery. When a lithium battery is used, charged lithium particles move through a barrier in the electrolyte from the cathode (the positive end) to the anode (the negative end), where they experience a chemical reaction that expels energy.
What do you get when you mix toxic liquids and flammable lithium salts? A standard lithium-ion electrolyte. Jeff Maranchi, APL’s material science program manager, says “in today’s lithium-ion chemistry, you have a recipe for disaster.” If the porous barrier that separates the anode from the cathode crumbles, it produces a short circuit with a significant amount of heat. When all that heat reaches a highly flammable material, such as the lithium-ion electrolyte next to the battery’s oxygen-rich cathode, whatever device it’s connected to will burst into flames.
Aqueous batteries, which were made 25 years ago, have electrolytes that are water-based and therefore are both nontoxic and nonflammable. Until recently, they had been too weak to be useful. The APL team found that by increasing the concentration of lithium salts and mixing the electrolyte with a polymer, they could raise the electrolyte potential from around 1.2 volts to 4 volts.
The team attached a commercially available cathode and anode to the electrolyte, the result is an incredible lithium-ion battery, unlike anything you’ve ever witnessed. It’s flexible, non-toxic, non-flammable, and transparent like a contact lens. The battery can be manufactured and operated in the open air without a case and can endure almost any kind of abuse.
How do you classify a nearly indestructible lithium-ion as such? During the experiments, Gerasopoulos and his team submerged the device in saltwater, used an air cannon to simulate a ballistic impact, cut it with scissors, and lit it on fire. Through each abusive test the battery didn’t give up, it kept pumping out electricity. Although a significant portion of the device was burnt it continued to operate for 100 hours more.
There are a few obstacles that the researchers have to overcome before the nearly indestructible lithium-ion is complete, including increasing the number of charging cycles it can handle. A standard smartphone battery can be recharged over 1,000 times, the APL battery starts to lose efficiency after as little as 100 cycles. Revolutionary technology has a humble start, somewhere in a lab, developed through trials, tribulations and sometimes fire.
