Researchers Double the Driving Range of EVs Using Everyday Household Materials

The research team at the Center for Energy Storage Research of the Korea Institute of Science and Technology (KIST), headed by Dr Hun-Gi Jung, has announced the development of new silicon anode materials that are capable of increasing battery capacity four times over when compared to current graphite anode materials. They also enable rapid charging to more than 80% capacity in as little as five minutes.

When applied to batteries for electric vehicles (EVs), Dr. Jung’s team believes that their new silicon anode materials could more than double their driving range. 

 

A graphic depicting the carbon-silicon complex mixture concocted by KIST researchers and to be used in EV battery systems, thus enabling their driving range to more than double. Image used courtesy of Korea Institute of Science and Technology (KIST) via Eurekalert.org.

 

Graphite is Limiting EV Batteries

Batteries currently used in EVs rely on graphite anode materials. However, these have low capacities, and these contribute to the relatively short drive times that EVs are infamous for. 

In the search for a material that could be used in the place of graphite, silicon – which has an energy storage capacity 10 times greater than graphite – has gained notoriety. It is thought by many to be the next-generation anode material that will spur the development of long-range EVs. 

However, silicon materials have not yet been widely commercialized because, during charge and discharge cycles, their volume rapidly expands, which decreases energy storage capacity. While there are many methods to enhance the stability of silicon as an anode material that have been postulated, their cost and complexity have prevented silicon’s in EV batteries from coming to fruition and replacing graphite. 

 

A photograph of the as-prepared SN-MCB powder devised by KIST researchers. Image credited to Hyun Jung Kwon et al., Center for Energy Storage Research, Korea Institute of Science and Technology

 

Using Everyday Materials to Prolong Drive Time

To improve the stability of silicon, Dr. Jung’s research team focused on using common everyday materials such as water, oil, and starch in novel experiments that could help bring silicon EV batteries closer to becoming a reality. 

In one experiment, Dr. Jung’s team dissolved starch and silicon in water and oil respectively and then mixed and heated them to produce carbon-silicon composites. To affix the carbon to the silicon, a simple thermal process used for frying food was utilized. This prevents the silicon anode materials from expanding during charge-discharge cycles. 

 

The Carbon-Silicon Material Composition Process

This composite material demonstrated a capacity four-times greater than that of graphite materials and stable capacity retention over 500 charge-discharge cycles. This was helped by carbon spheres which prevent silicon’s typical volume expansion, thereby enhancing stability. It was also demonstrated that the materials enable batteries to charge to more than 80% capacity in as little as five minutes. The use of carbon and the rearrangement of the silicon structure also resulted in a high output.

"We were able to develop carbon-silicon composite materials using common, everyday materials and simple mixing and thermal processes with no reactors," said Dr. Jung. 

He added, "The simple processes we adopted and the composites with excellent properties that we developed are highly likely to be commercialized and mass-produced. The composites could be applied to lithium-ion batteries for electric vehicles and energy storage systems (ESSs)."

 

EV Battery Sustainability Considerations 

The use of silicon and biomaterials to develop a better EV battery also has several benefits for sustainability and the environment. Developing a more environmentally friendly EV battery is at the top of the U.S. Energy Department’s agenda. It also addresses graphite sourcing problems that the U.S. has been contending with since the 1990s when domestic mining ceased.