Gel makes batteries better

New storage material improves the energy density of the lithium-ion battery

Battery researcher at work: Stefan Koller from the Institute for Chemical Technology of Materials with a diploma student © Lunghammer / TU Graz
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Powerful energy storage systems for the automotive industry or mobile phone batteries and notebooks that provide sufficient energy for long-term use - Graz scientists make these visions a bit more realistic: The researchers have developed a new process that makes silicon usable for lithium-ion batteries.

Its storage capacity is ten times higher than the previously used graphite and can therefore hope for significant improvements for users.

New storage materials wanted

Modern electrical appliances want more energy and the automotive industry is also longing for ever more powerful energy storage systems. The technological development in battery research has long been insufficient: "The development of the next generation requires a real revolution. We need new storage materials for lithium-ion batteries, "explains battery researcher Stefan Koller from the Institute of Chemical Technology of Materials at Graz University of Technology (TU).

Together with colleagues from science and industry, he has succeeded in developing such a carrier material for electrochemical reactions at low cost.

Silicon gel on graphite

In the newly developed method, the researchers use a silicon-containing gel and apply it to graphite as the carrier material. "The graphite acts as a buffer to cushion the large volume changes of silicon during lithium-ion uptake and release, " explains Koller. display

Silicon has about ten times higher lithium-ion storage capacity than the previously commercially used graphite. The new material can thus save more than twice the amount of lithium ions with an unchanged lifetime. This technique is far more favorable than previously known, in which the silicon is deposited from the gas phase. "The challenge remains the poor storage density of the materials in the counter electrode in the entire battery, but we are also doing intensive research on this, " concludes Koller.

Process already patent pending

Their findings - developed as part of the EU project "NanoPoliBat" - have meanwhile been submitted to a patent by the researchers together with a cooperation partner.

(idw - Graz University of Technology, 29.10.2009 - DLO)