Scientists make almost invincible lithium-ion battery
|Invincible lithium-ion battery|
This new type of battery can be cut, folded, soaked, shot, and lit on fire – and it is still fine. Lithium ion batteries have shaped the modern world. These power pouches are at the heart of most rechargeable electronics, from cellphones and laptops to vaults and electric cars. But while they are great at holding a charge and have a high energy density, lithium-ion batteries are not without their problems. Their dependence on toxic, flammable materials means that the smallest defect can result in an explosion in the gadget.
A team of researchers led by physicists at the Johns Hopkins Applied Physics Laboratory claimed a safe battery was feasible and developed lithium-ion batteries that seemed resistant to failure over the past five years. The rugged battery, which worked with researchers at the University of Maryland for the first time in 2017, was unveiled, can be cut, shot, bent, and soaked without power interruption. At the end of last year, the Johns Hopkins team pushed it further, making it fireproof and raising its voltage to a level comparable with a commercial product. Samsung, eat your heart’s food.
|Invincible lithium-ion battery test|
The core of the new battery is a mixture of electrolyte lithium salts and a soft plastic material that will not be trapped in a fire or explosion.
The secret to making an indestructible battery comes under the electrolyte, says Konstantinos Gerasopoulos, a senior scientist at APL, the chemical gol that separates the positive and negative ends of the battery. When you use a lithium-ion battery, the charged lithium particles travel from the anode (negative end) to the cathode (positive end) through a barrier in the electrolyte, where they undergo a chemical reaction that produces energy.
Most lithium-ion electrolytes are a mixture of flammable lithium salts and toxic liquids, meaning “in today’s lithium-ion chemistry you have a recipe for disaster,” says Jeff Maranchi, materials science program manager at APL. If the permeable resistor that separates the cathode from the anode crumbles, it creates a short circuit – and a lot of heat. When all this heat collides with a highly flammable substance like lithium-ion electrolyte next to the oxygen-rich cathode in the battery, you get a burning electronic device on your hands.
Aqueous batteries overcome all these problems, including water-based electrolytes which are both non-flammable and non-toxic. They have been around for 25 years but are too weak to be useful. What the APL team discovered is by increasing the concentration of lithium salts and mixing the electrolyte with a polymer – a very soft plastic-like material – they can bump electrical capacities from about 1.2 volts to 4 volts, comparable to commercial lithium-ion batteries.
When Gerasopoulos and his colleagues attached a commercially available anode and cathode to this plasticity electrolyte, they ended up with a lithium-ion battery. It is clear and flexible like a contact lens, nontoxic and nonflammable, and can be manufactured and operated in the open air in no case. On top of that, it can withstand any kind of abuse.
During the tests, which you can see here, the APL team submerged the equipment in saltwater, cut it with scissors, used an aerial cannon to simulate a ballistic effect, and opened fire. Through each test, the battery continued to pump electricity. After a test by fire, the sacral part was cut off and it continued to function normally for 100 hours.
Maranchi says the new water-based battery is not just a laboratory curiosity.The APL team is already in negotiations with undeclared suppliers, who say they will, without trouble, Incorporate the new chemical and formation element in current lithium-ion production facilities. It could be on the market within two years, he says, and go where no batteries have gone before.
Because it is flexible, it can be incorporated into wearable electronics, even ultimately integrated directly into clothing fibers. Its ruggedness also suggests new uses in military and scientific applications such as a host of autonomous underwater vehicles, drones, and satellites.
There are still some technical hurdles to overcome, such as increasing the number of cycles that charge an aqueous battery. A typical smartphone battery can be recharged more than 1,000 times, but this APL battery starts losing efficiency after just 100 cycles. The electrolyte chemistry should be fine-tuned, Gerasopoulos says.
Finally, the era of exploding gadgets may come to a close.