Scientists from China and the United States develop high-performance organic polymer electrodes or realize low-cost / environmentally friendly sodium ion batteries

Posted 2024-04-11 00:00:00 +0000 UTC

According to foreign media reports, lithium ions in the next generation may be replaced by more abundant and environmentally friendly alkali metals or multivalent ions. However, the main challenge is to develop stable electrodes that combine high energy density with fast charge discharge rates. Recently, scientists in China and the United States have developed a high-performance electrode made of organic polymer, which can be used in low-cost, environmental friendly and durable sodium ion batteries. (image source: Wiley) at present, lithium-ion battery is the most advanced technology, which can be used in portable devices, energy storage systems and electric vehicles, and lithium-ion battery technology won the Nobel Prize this year. However, the next generation of batteries is expected to use cheaper, safer and more environmentally friendly materials to achieve higher energy density and capacity. At present, the most developed battery types basically use the same charge and discharge technology as lithium batteries, but usually lithium ions are replaced by cheap metal ions such as sodium, magnesium and aluminum. However, this substitution also makes it necessary to make significant adjustments to the electrode materials. Organic compounds are good electrode materials. Firstly, they do not contain harmful and expensive heavy metals. Secondly, they can be used for different purposes. However, the disadvantage is that it will dissolve in the liquid electrolyte, resulting in electrode instability. Chunsheng Wang of the University of Maryland and his team, in collaboration with the international scientific team, have launched an organic polymer that can be used as a cathode material for batteries with high capacity, rapid discharge and insoluble. According to this study, in the sodium ion battery, this kind of polymer is superior to the current polymer and inorganic cathode in capacity transfer and capacity retention, and in the multivalent magnesium ion and aluminum ion battery, this kind of performance is not far behind. Scientists have found that hexaazatrinaphthalene (hatn) is a very suitable cathode material, and the compound has been tested in lithium batteries and supercapacitors to prove that it can become a high-energy density cathode, which can be quickly inserted into lithium ion. However, like most organic materials, hatn will dissolve in the electrolyte, resulting in the cathode instability during the charge discharge cycle. Scientists explained that the key now is to stabilize the structure of the material by connecting individual molecules, resulting in an organic polymer called polymer hatn or phatn, which can make sodium, aluminum and magnesium ions have rapid reaction power and high capacity. After the battery was assembled, the scientists tested the phatn cathode with high concentration electrolyte, and found that the non lithium ion had excellent electrochemical performance. The sodium battery can work at a high voltage of up to 3.5V. Even after 50000 cycles, its capacity can still be maintained above 100mah per gram. The researchers believe that this kind of polymerized p-diazobenzene cathode (p-diazobenzene is an organic substance based on hatn, an aromatic nitrogen rich organic substance with fruit flavor) can realize the next generation rechargeable battery with environmental protection, high energy density, fast charging and discharging and super stability.

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