Battery-powered cars offer many environmental benefits, but a car with a full tank of gasoline can travel further. By improving the energy capacity of lithium-ion batteries, a new electrode made from iron oxide nanoparticles could help electric vehicles to cover greater distances.
Electric vehicles could travel further when powered by a higher-capacity lithium-ion battery made with inexpensive iron oxide nanoparticles.
Developed by Zhaolin Liu of the A*STAR Institute of Materials Research and Engineering, Singapore, and Aishui Yu of Fudan University, China, and co-workers, the electrode material is inexpensive, suitable for large-scale manufacturing and can store higher charge densities than the conventional electrodes used in lithium-ion batteries1.
These batteries store and release energy by shuttling lithium ions between two electrodes connected in a circuit. During charging, lithium ions escape from the cathode, which is made from materials such as lithium cobalt oxide. The ions migrate through a liquid electrolyte and into the anode, which is usually made of graphite riddled with tiny pores. When the battery discharges, the process runs in reverse, generating an electrical current between the electrodes.
Iron oxides have a much higher charging capacity than graphite, but the process is slow. Forcing lithium ions into the material also changes its volume, destroying the anode after just a few charging cycles.
Liu, Yu and team reasoned that an anode made from iron oxide nanoparticles would charge more quickly, because its pores would give ready access to lithium ions. The pores may also allow the material’s structure to change as the ions pack inside.
The researchers made 5-nanometer-wide particles of an iron oxide known as á-Fe2O3, simply by heating iron nitrate in water. They mixed the particles with a dust called carbon black, bound them together with polyvinylidene fluoride and coated the mixture onto copper foil to make their anodes.
During the first round of charging and discharging, the anodes showed an efficiency of 75–78%, depending on the current density used. After ten more cycles, however, the efficiency improved to 98%, almost as high as commercial lithium-ion batteries. Research by other teams suggests that during the first few cycles, the iron oxide nanoparticles are broken down until they reach an optimum size.
After 230 cycles the anode’s efficiency remained at 97%, with a capacity of 1,009 milliamp hours per gram (mA h g−1 ) — almost three times greater than commercial graphite anodes. The material experienced none of the degradation problems that have plagued other iron oxide anodes.
The team is now working to optimize the nanoparticle synthesis and increase the efficiency of the anode’s initial charging cycles.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and EngineeringAssociated links
Electromagnetic water cloak eliminates drag and wake
12.12.2017 | Duke University
Two holograms in one surface
12.12.2017 | California Institute of Technology
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Physics and Astronomy
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering