Batteries using lithium metal anodes rather than lithium ions promise high capacities, but a tendency to grow internal cell-shorting spike-like metal dendrites makes them a risky, or even unsafe, proposition if liquid electrolytes are used.
Solid inorganic or polymer electrolytes can block dendrite growth, but bring drawbacks such as low conductivity.
Now the Gatech team has thrown its hat in the ring with an in-between electrolyte, calling it a ‘rubber electrolyte’. It is “a three-dimensional interconnected plastic crystal phase within the robust rubber matrix”, said the university. “This unique structure has resulted in high ionic conductivity, superior mechanical properties and electrochemical stability.”
The electrolyte can be made in-place using a polymerisation process which creates a smooth robust interface with electrode surfaces and the “characteristics of the rubber electrolytes prevent lithium dendrite growth and allow for faster moving ions, enabling reliable operation of solid-state batteries even at room temperature”, added Gatech.
Tested with a LiNi0.83Mn0.06Co0.11O2 cathode, a Coulombic efficiency of 100% has been claimed and storage at 410Wh/kg (for just the electrode and electrolyte).
The next step is to increasing cycle time and decreasing charging time through better ionic conductivity.
Georgia Tech worked with the Korea Advanced Institute of Science and Technology, and the work is published as ‘Elastomeric electrolytes for high-energy solid-state lithium batteries‘ in Nature (abstract available without payment).
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