Graphene makes Super batteries that can be charged for a very, very long life.

Scientists at Zhejiang University used graphene membrane as a positive material to develop a new type of aluminum-graphene battery. The battery has a very long life, can be fully charged in a very short period of time, and can work properly within the temperature range of minus 40 degrees Celsius to 120 degrees. This innovation points out important directions for the practical application of aluminum ion batteries.

Compared with lithium batteries that are widely used today, aluminum ion batteries are a new type of battery that is better in many ways. In fact, the key to use is to find suitable cathode materials. The Zhejiang University's high polymer series professor's task group selected graphene as a magical material that has repeatedly created new breakthroughs. The unique graphene membrane was prepared as a positive material in an innovative process, which greatly improved the overall performance of aluminum ion batteries. The prospect of competing with the mainstream lithium batteries and supercapacitors is very promising. Related papers have been published in the internationally renowned journal Science Advances. The first author of the paper is Dr. Chen Hao, a member of the research group.

Some of the obvious flaws of lithium batteries are felt by everyone using a smartphone. For example, battery life is limited. Many mobile phones make consumers feel that the battery is not durable. After a year or two of use, the battery's battery life ability is greatly reduced. Another example is the unstable battery performance at low temperature and high temperature. Some mobile phones in the cold environment in the northeast of the instant shutdown, some suddenly exploded when charging, because of the normal working temperature range of lithium batteries limited.

In contrast, the aluminum graphene batteries developed by the superb team showed obvious advantages. "The capacity of the battery is its endurance. General batteries will continue to reduce their capacity as they are repeatedly charged and discharged. This is what we call 'not durable'. "Aluminum-graphene batteries perform well at this point," said Xuhanyan, a second author and panellist. This type of battery undergoes 250,000 charge-discharge cycles, the charging and discharge rate is still as high as 91 %, and the capacity loss is very small. In other words, if a smartphone uses the battery, it can be charged even 10 times a day for nearly 70 years.

The doubling performance of this aluminum-graphene battery is also very good, showing that it can be quickly charged under large currents while maintaining a higher specific capacity. "Some smartphones now also have fast-charging capabilities. It seems that the battery is quickly full and the actual life span is not long. And the new battery now has laboratory data of 1.1 seconds, which is less than the capacity loss. "This shows that if you use a mobile phone in the future, it is entirely possible to charge for 5 seconds and talk for 2 hours. "

Aluminum-graphene batteries light up the LED string with "ZJU120" printed on it

Aluminum graphene batteries exhibit high multiplier performance and long cycle life, similar to supercapacitors that are now used for rapid start-up of cars. The aluminum-graphene battery has a higher energy density, which means that it can be made smaller and lighter, while providing constant energy.

In general, lithium batteries are compact and light, providing more energy, but they can not withstand repeated charging and poor performance. Supercapacitors, on the other hand, are bulky and bulky. The two are often used in conjunction with each other. "Aluminum graphene batteries do not lose Super capacitors in terms of ratio performance and cycle life, far exceeding lithium batteries. Although there is a gap in energy density with lithium batteries, it significantly exceeds supercapacitors. "The aluminum graphene battery has shown a certain advantage in the face of the two opponents, lithium batteries and supercapacitors, and can be called a" super battery, "said Gao.

The battery won't burn in the heat.

Aluminum-graphene batteries also have some other batteries that are unmatched. At a low temperature of minus 40 degrees, the aluminum-graphene battery can still steadily charge and discharge 1,000 times, the high temperature to 100 degrees, and the stable charge and discharge 45,000 times. Even if the core is exposed to Yuhuoyan, it will not catch fire or explode. This wide temperature range lays the foundation for the future use of aluminum ion batteries under extreme temperature conditions. This battery also has a good flexibility, and its capacity is completely maintained after 10,000 bends, demonstrating its application potential in wearable flexible electronic devices.

The excellent performance of the "super battery" stems from the excellent microstructure of the graphene membrane as a positive material and its macroscopic performance. Many of the important properties of the battery depend on the extent to which electrons and ions can flow smoothly between positive and negative poles. Compared to other positive materials, the graphene film prepared by the superb task group has high quality lattice defects, high orientation, and continuous channels, just like highways that extend in all directions, allowing electrons and ions to travel unimpeded.

In the field of aluminum ion battery research, Professor Daihongjie of Stanford University made pioneering work, first of all to achieve aluminum ion batteries with higher capacity and longer cycles. Professor Yuyan of China University of Science and Technology has realized ultra-fast and long-cycle sodium ion batteries. The advances brought by superb teams have made the application of aluminum batteries in high-power energy storage systems more promising. The superb said that it is also necessary to see that the current positive pole has more room for improvement than the capacity, output voltage, and surface load. The energy density is not enough to compete with lithium ion batteries. In the future, it is necessary to further improve the energy density on the basis of maintaining high power density. In addition, the current classical Ionic liquid electrolytes are more expensive, and if cheaper electrolytes can be found, the commercial prospects of aluminum ion batteries will be wider.

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