Imperial College London develops non-toxic batteries -Lithium - Ion Battery Equipment
At present, the most widely used battery is lithium-ion battery, which has a relatively high capacity (can store a large amount of charge), but cannot be quickly charged or discharged. In addition, there are organic electrolytes and other hazardous and flammable materials that require careful handling and placement.
Compared with traditional lithium-ion battery, this battery prototype has less charge stored, but it can be charged and discharged in a few seconds. The battery is made of polymer (forming long molecular chains of plastic). This material has an additional advantage. It can change the color when the battery is charged, so that the user can easily read the charging state of the battery.
The battery prototype can improve the charging speed of existing batteries, reduce the toxicity of existing batteries, or pave the way for manufacturing new types of batteries.
Recyclable battery
Dr. Alexander Giovannitti, the co lead author of the study, said: "The materials we used to create the battery prototype can be manufactured at a lower cost, and combined with the use of non-toxic and nonflammable water-based electrolytes, which may open up a feasible way to develop recyclable batteries."
The battery with fast charging speed but low capacity can be used in a series of applications. The energy in such applications needs to be replaced quickly, but the battery may not be small. For example, the energy generated by automobile braking can be used later to accelerate the automobile.
From a broader perspective, when renewable energy such as solar energy or wind energy is used as part of the national or local power grid, it can only provide energy intermittently. However, a battery system that can store energy quickly can transmit power back to the power grid when needed, which is very valuable for maintaining the stable supply of the power grid.
The research team said that further research is needed to adapt the battery prototype to the above application fields, but its design principle may be applicable to various energy storage devices being developed.
Design of new materials
Previously, polymer materials have been successfully used in batteries as flexible additives or electrolytes to separate positive and negative electrodes. However, it has proved to be very challenging to use this material as an active material for battery electrodes operating in water.
This breakthrough comes from the design of polymer materials, which can absorb or release positive or negative ions from brine at a fast and reversible speed without degradation. When the device is charged, such ions will be attracted to the electrode with opposite charge.
Water based batteries are non-toxic and ideal batteries, but it is difficult for such batteries to make ions in water exchange reversibly with electrodes. The research team solved this problem by designing side chains to connect to the "backbone" of conductive polymers. By using polar materials on the side chains, researchers have developed highly hydrophilic electrodes.
According to this principle, researchers can make positive and negative electrodes, which can absorb positive and negative ions from water. Therefore, researchers have obtained materials for making batteries. Since the polymer backbone network is already flexible and can expand and contract during battery charging and discharging, additives are no longer needed.
Dr. Davide Moia, the co lead author, said: "The use of salt water has got rid of the concerns about toxicity and flammability, but compared with other organic electrolytes, such water-based electrolytes are not easy to use, because they will limit the charging and discharging power of the equipment."