Researchers at Purdue University in the US have developed a net-like nanochain of antimony to boost the performance and safety of the electrode in a lithium ion coin cell battery.
The researchers compared a nanochain electrode to a current graphite one and found that the coin cell batteries with the nanochain electrode achieved double the lithium-ion capacity for just 30 minutes of charging across 100 charge-discharge cycles. This is a signficant improvement in performance, and also provides safer fast charging.
Some types of commercial batteries already use carbon-metal composites similar to antimony metal negative electrodes, but the material tends to expand up to three times as it takes in lithium ions, causing it to become a safety hazard as the battery charges.Applying a reducing agent and a nucleating agent allowed the team to connect the tiny antimony particles into a nanochain shape that accommodates the expansion. The particular reducing agent the team used, ammonia-borane, is responsible for creating the the pores inside the nanochain - that accommodate expansion and suppress electrode failure.
The team applied ammonia-borane to several different compounds of antimony, finding that only antimony-chloride produced the nanochain structure.
"Our procedure to make the nanoparticles consistently provides the chain structures," said P. V. Ramachandran, a professor of organic chemistry at Purdue.
The nanochain also keeps lithium ion capacity stable for at least 100 charging-discharging cycles. "There's essentially no change from cycle 1 to cycle 100, so we have no reason to think that cycle 102 won't be the same," said Vilas Pol, a Purdue associate professor of chemical engineering.
The electrode design has the potential to be scalable for larger batteries, the researchers say. The team plans to test the design in pouch cell batteries next.