The number of lithium ions stored in the battery’s negative electrode material determines the time for which the battery of a phone or a computer can last. In case when the battery runs out of the ions, it cannot generate electrical current and hence the device fails to function.
Materials with a higher lithium ion storage capacity are usually too heavy or have the wrong shape to replace graphite, the electrode which is used today in the batteries.
Latest research conducted by Purdue University engineers and scientists have found a new way to restructure this material into an inventive electrode design. This would further allow to increase the battery life and make it more stable, in addition to reducing the charging time.
A net like structure known as ‘nanochain’ of antimony, will increase the lithium ion charge capacity in the batteries. For the study, scientists compared nanochain electrodes to graphite electrodes. It was found that coin cell batteries when charged for 30 minutes with nanochain electrode could produce double lithium-ion capacity for 100 charge-discharge cycles.
Certain types of commercial batteries use carbon-metal composites which are similar to antimony metal negative electrodes, the material however expands three times when it takes lithium ions, it thus becomes a safety hazard when the battery is charged.
“You want to accommodate that type of expansion in your smartphone batteries. That way you’re not carrying around something unsafe,” commented Vilas Pol, a Purdue associate professor of chemical engineering.
The current study therefore applied chemical compounds, a nucleating agent and a reducing agent in order to connect tiny antimony particles into a nanochain shape to accommodate the necessary expansion. Reports allege, the team used ammonia-borane to create empty spaces, the pores inside to accommodate expansion and suppress electrode failure.
Furthermore, the nanochain also keeps the lithium ion capacity stable for 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,” commented Pol.
The latest design which is scalable for larger batteries will be further tested in pouch cell batteries.