Confining dendrite growth

1 min read

A porous electrolyte that effectively lengthens the route ions must take to travel from the anode to the cathode and back has been created by Snehashis “Sne” Choudhury, Ph.D. ’18 of Cornell University.

What we have now [in lithium-ion battery technology] is actually at the limits of its capabilities," says Professor Lynden Archer of Cornell University. "The lithium-ion battery, which has become the workhorse in powering new electronics technologies, operates at over 90% of its theoretical storage capacity. Minor engineering tweaks may lead to better batteries with more storage, but this is not a long-term solution.

"You need a kind of radical mindset change," he continues, "and that means that you've got to almost start at the beginning."

The team says it has taken steps towards this venture with its porous electrolyte. Using a reaction procedure the Archer group previously introduced in 2015, the team employed ‘cross-linked hairy nanoparticles’ - a graft of silica nanoparticles and a functionalised polymer (polypropylene oxide) to create the electrolyte. The hope is this will offer a solution to short-circuiting and fire hazards that can occur in rechargeable batteries that use energy-dense metallic lithium anodes.

The team says it has been able to confine dendrite growth by the structure of the electrolyte itself, which can be controlled chemically.

The team has created a cell that enables the team to visualise what is occurring at the lithium-metal interface.

Moreover, it's long been held that, in order to suppress dendrite growth, the separator inside the battery must be stronger than the metal it is trying to suppress. However, the porous polymer separator - with average pore sizes below 500nm - were shown to arrest the growth.