Novel System Sequesters CO2 And Generates Electricity

A recent study, affiliated with UNIST (South Korea) has unveiled a novel system, capable of producing hydrogen and electricity quickly and effectively while cutting carbon dioxide (CO2) emissions significantly.  Published in the journal Nano Energy, this breakthrough has been carried out by Professor GunTae Kim and his research team in the School of Energy and Chemical Engineering at UNIST. In this study, the research team succeeded in developing a membrane-free aqueous metal-CO2 battery. Unlike the existing aqueous metal-CO2 systems, the new battery is not only easier to manufacture, but also allows continuous operation with one type of electrolyte.

The research team designed a membrane-free (MF) Mg-CO2battery, as an advanced approach to sequester CO2 emissions by generating electricity and value-added chemicals without any harmful by-products. According to the research team, their MF Mg-CO2 battery operates based on the indirect utilization of CO2with facile hydrogen generation process. It has been also found that the new battery exhibits high faradaic efficiency of 92.0%.

In order to translate the newly-developed laboratory-scale MF Mg-CO2 battery technology into a commercial reality, we have envisioned an operational prototype system that produces electricity and value-added chemicals, as a cornerstone to better support sustainable human life from CO2 and earth-abundant renewable power (e.g., wind, solar, seawater),” noted the research team.

The MF Mg-CO2 battery system has a structure similar to that of hydrogen fuel cells for use in cars, since it only requires a Mg-metal negative electrode, an aqueous electrolyte, and a positive-electrode catalyst. However, unlike the existing fuel cells, they are based on aqueous electrolytes. As a result, the newly-developed MF Mg-CO2 battery had successfully sequestered CO2 emissions by generating electricity and value-added chemicals without any harmful by-products.

Our findings indicate great benefits for the newly-developed MF Mg-CO2 battery technology to produce various value-added chemicals of practical significance and electricity from CO2without any wasted by-products,” noted the research team. “Through this we have opened the door to electrochemical utilization of CO2 with indirect circulation for future alternative technologies.”

Source: https://www.eurekalert.org/

How To Extend The Charge-to-charge Life of Phones And Electric Cars By 40 %

The need to store energy for portable devices, vehicles and housing is ever increasing.The transformation from fossil fuels to renewable energy sources need to be hastened to decrease greenhouse gases and limit global warming. The utilization of wind and solar power requires effective storage system to ensure continuous energy supply as a part of smart grid. Li-ion batteries are considered to be the best route for many advanced storage applications related to the clean electricity due to their high energy density.

The latest lithium-ion batteries on the market are likely to extend the charge-to-charge life of phones and electric cars by as much as 40 percent. This leap forward, which comes after more than a decade of incremental improvements, is happening because developers replaced the battery’s graphite anode with one made from silicon. Research from Drexel University and Trinity College in Ireland now suggests that an even greater improvement could be in line if the silicon is fortified with a special type of material called MXene.

Regarding the present Li-ion batteries, one of the limiting factors in their performance is the anode material that most commonly is graphite. Silicon is a promising material for Li-ion battery anodes: By using silicon instead of graphite, the energy density of a battery cell ccould be increased by 30 %. To achieve this, several obstacles have to be overcome: First, silicon experiences a volume expansion of 300 % when lithiated. During discharging, the particles tend to fracture and lose contact. Secondly, the volume expansion prevents the formation of a stable electrode-electrolyte interface resulting in a continuous decomposition of the electrolyte. These two reasons are main causes for the limited use of silicon in commercial batteries.

The image shows PSi microparticles connected to each other with CNTs to improve the conductivity of the material

Both of the above mentioned problems with silicon material can be avoided by designing optimal porous structures of mesoporous silicon (PSi). Porosity of PSi needs to be high enough for the material to be able to withstand the volume expansion but also low enough so that the volumetric capacity/energy density is still better than for graphite anodes.

Source: https://www.nature.com/

Cartilage-like Material Boosts Batteries Durability

Your knees and your smartphone battery have some surprisingly similar needs, a University of Michigan professor has discovered, and that new insight has led to a “structural battery” prototype that incorporates a cartilage-like material to make the batteries highly durable and easy to shape.The idea behind structural batteries is to store energy in structural components—the wing of a drone or the bumper of an electric vehicle, for example. They’ve been a long-term goal for researchers and industry because they could reduce weight and extend range. But structural batteries have so far been heavy, short-lived or unsafe.

In a study published in ACS Nano, the researchers describe how they made a damage-resistant rechargeable zinc battery with a cartilage-like solid electrolyte. They showed that the batteries can replace the top casings of several commercial drones. The prototype cells can run for more than 100 cycles at 90 percent capacity, and withstand hard impacts and even stabbing without losing voltage or starting a fire.

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A battery that is also a structural component has to be light, strong, safe and have high capacity. Unfortunately, these requirements are often mutually exclusive,” said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering, who led the research.

To sidestep these trade-offs, the researchers used zinc—a legitimate structural material—and branched nanofibers that resemble the collagen fibers of cartilageAhmet Emrehan Emre, a biomedical engineering PhD candidate, sandwiches a thin sheet of a cartilage-like material between a layer of zinc on top and a layer of manganese oxide underneath to form a battery

Nature does not have zinc batteries, but it had to solve a similar problem,” Kotov said. “Cartilage turned out to be a perfect prototype for an ion-transporting material in batteries. It has amazing mechanics, and it serves us for a very long time compared to how thin it is. The same qualities are needed from solid electrolytes separating cathodes and anodes in batteries.”

In our bodies, cartilage combines mechanical strength and durability with the ability to let water, nutrients and other materials move through it. These qualities are nearly identical to those of a good solid electrolyte, which has to resist damage from dendrites while also letting ions flow from one electrode to the other.

Source: https://news.umich.edu/