Compared to other battery technologies, Lithium ion (Li-ion) batteries have a relatively high energy density and long lifetime. Their development over the years has enabled them to be the battery technology of choice in a number of areas.
These include powering portable electronics, and electric vehicles. While they possess desirable characteristics and outperform other commercially available technology, they are not without their problems however.
Li-ion batteries can dangerously explode under the right conditions. This is cause for great concern. Their potential danger is such that airlines only allow this battery technology in carry-on baggage.
When the topic of exploding Li-ion batteries comes up, the infamous Samsung Galaxy Note 7 immediately comes to mind. Several batteries of this eventually recalled Samsung device simply exploded.
The controversy associated with exploding hoverboards also pops up. The common denominator between these 2 scenarios is that the explosions were as a result of faulty Li-ion batteries.
While these 2 cases received a lot of attention, other devices containing Li-ion batteries have exploded before. Although it is rare with properly quality controlled batteries, an exploding Li-ion battery is a serious risk which should not be taken lightly.
A group of researchers from Drexel University recognized that there are still risks associated with this battery technology and have come up with an interesting twist to this story. They are using diamonds to make the batteries more stable! I really want to tell you all about this novel solution but first, let’s go through some background information.
The main components of a battery are as follows:
Positive and negative terminals: These are the points of contact for electrical equipment. They allow electricity to pass from the battery to the equipment.
Anode and cathode: Chemical reactions occur at these electrodes which are responsible for the generation of a current.
Electrolyte: This is a medium which allows for the flow of charge between the cathode and anode.
How Lithium Ion Batteries Fail and Subsequently Explode
Explosions in Li-ion batteries mainly occur due to the short circuiting of the positive and negative terminals. The formation of structures called dendrites on the inside of batteries can cause these short circuits.
A short circuit is an electrical connection which causes excessive current flow and generates heat.
Dendrites are build-ups which can form on the inside of a Li-ion battery.
Essentially, these dendrites short circuit the positive and negative terminals of the battery, generating large amounts of heat and igniting the electrolyte inside of the battery.
Most electrolytes are flammable. When ignited, an electrolyte will usually cause an explosion.
Thankfully measures safety mechanisms exist in high quality Li-ion batteries.
In order to prevent dendrite formation, Li-ion batteries currently on the market use a graphite electrode which is filled with Lithium. While this configuration, suppresses dendrite formation, it also reduces the energy density of the battery.
If this electrode is made of pure Lithium, batteries would have around 10 times their current capacity. However, they would also be more likely to explode because of an increased potential for dendrite formation.
This method is quite effective. However, sub par quality batteries tend not to get it quite right which can result in explosions. While this is the case, the method described next could potentially be an even better safety mechanism.
Drexel Researchers Novel Solution
The Drexel team came up with a novel solution to maintain the energy density of pure Lithium while enhancing safety. They designed a battery which makes use of a pure Lithium electrode. In order to counteract dendrite formation, they infuse the electrolyte solution with nanodiamonds.
Nanodiamonds are extremely small diamonds.
The nanodiamonds drastically reduce the risk of the chemical reaction occurring at the electrodes resulting in dendrite formation. Lithium is coated onto one of the electrodes during battery discharge. The nanodiamonds facilitate a uniform coating, preventing dendrites.
The team admits that while this method is quite effective based on their tests, it is difficult to say that their method would completely eliminate dendrite formation. With that being said, this method is quite promising as it enhances safety and allows for a higher capacity battery.