Scientists at Stanford University in Palo Alto, California announced last week that they’ve developed the initial technology for a battery with a lifespan of nearly 100-times that of a conventional lithium ion battery.
Using a nanoparticle of copper, copper hexacyanoferrate, the scientists developed a battery electrode that survived 40,000 cycles of charging and discharging, compared to 400 cycles for a lithium-ion electrode. Even after 40,000 charges, the battery still managed to retain 80-percent of its original charge capacity, according to Stanford.
The researchers believe their technology will provide an enormous boost to the wind and solar energy sectors, allowing far larger quantities of excess clean energy to be generated and stored for later usage than can be attained today.
“That is a breakthrough performance - a battery that will keep running for tens of thousands of cycles and never fail,” said Yi Cui, an associate professor at Stanford who worked on the project with colleague Robert Huggins and graduate student Colin Wessells, in a release from the university.
The three authored a paper on their finding that was recently published in the journal Nature Communications.
The team settled on copper hexacyanoferrate crystals because they contain an “open framework,” that is, large enough gaps to accomodate the flow of ions in and out without damaging the electrode. Common lithium ion batteries eventually fail after many cycles to damage to the electrode structure, which expands and contracts as lithium ions flow in and out.
However, as the researchers themselves pointed out, they are missing one key ingredient before they can even begin building their long-living battery: An anode.
Every galvanic battery contains an electrolyte and two electrodes: a cathode and an anode.
Although commonly represented by a positive and negative symbol, respectively, a battery’s two electrodes are actually technically distinguished by their relationship to the directional flow of the battery’s current. The current always flows from the cathode out of the battery and from outside, into the battery, through the anode.
The Stanford team created the electrode using copper hexacyanoferratte, but is still searching for the proper material for the anode, although they say they have several candidates in mind.
On the plus side (no pun intended), the team notes that another component of the battery, the electrolyte, is made up of an inexpensive water-based compound, compared to lithium-ion batteries, which typically rely on organic electrolytes or molten salts as electrolytes, which are more expensive and make up the majority of the cost of li-ion batteries, according to a separate analysis published recently by Carnegie Melon University.
We’ve reached out to Stanford for more on the team’s breakthrough and will update when we receive a response.