Introduction

Kiel is conducting research into more powerful silicon batteries

 

Kiel University and RENA Technologies are developing anodes made of pure silicon in a joint research project. The project aims to develop powerful e-mobility batteries.

  • Client

    Kiel University and RENA Technologies

  • Services

    To develop powerful e-mobility batteries.

  • Technologies

    Storage technology

  • Dates

    16/05/2018

Description

Longer duration, greater cruising range, shorter recharging processes – the performance of rechargeable batteries is crucial for expanding e-mobility. Silicon's enormous storage capacity gives it considerable potential, as it can store up to ten times more energy than graphite anodes in conventional lithium-ion batteries. The semi-metal is also found in almost unlimited quantities.

 

Silicon's mechanical instability has nevertheless made it very difficult to use for storage technology to date. A joint research project of the Kiel University (CAU) and RENA Technologies , funded by the Federal Ministry of Education and Research, aims to solve this problem. The team is working on anodes made of 100% silicon, whose storage potential is fully exploited thanks to targeted surface structuring at the micro level. The project's declared goal is to develop high performance silicon batteries that can be economically produced on an industrial scale.

 

Longer life times, larger ranges and faster recharging—developments such as electric mobility or the miniaturisation of electronics require new storage materials for batteries. With its enormous storage capacity, silicon would potentially have decisive advantages over the materials used in commercial available lithium-ion batteries. But due to its mechanical instability, it has so far been almost impossible to use silicon for storage technology. A research team from the Institute for Materials Science at Kiel University, in cooperation with the company RENA Technologies GmbH, is developing anodes made of 100% silicon, as well as a concept for their industrial production. Through targeted structuring of its surface at the micrometer level, the team can fully exploit the storage potential of silicon. This opens up a completely new approach to rechargeable batteries, as well as the energy storage of tomorrow.

 

Silicon has long been a potential candidate for the e-lectric mobility, according to materials scientist Dr. Sandra Hansen. "Theoretically, silicon is the best material for anodes in batteries. It can store up to 10 times more energy than graphite anodes in conventional lithium-ion batteries." Electric cars could drive further, smartphone batteries could last longer, and recharging would be significantly faster. An additional advantage of the semiconductor material is its unlimited availability—after all, sand consists largely of silicon dioxide. "Silicon is the second most abundant element on earth after oxygen, and thus an almost unlimited cost-effective resource," said Hansen.

 

However, so far the life time of silicon anodes was far too short to really use them in chargeable and rechargeable batteries. The reason for this is the high sensitivity of the material. During charging, lithium ions move back and forth between the anode and cathode. Silicon, as the material with the highest energy density, can take up a remarkable number of lithium ions. While doing so, it expands by 400 percent, and would break in the long run.

 

Kiel University and RENA Technologies (Germany)

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