Lithium batteries have improved since their discovery in the 1990s, and since then their density has tripled, and their safety has increased. However, degradation of batteries over time is usually their greatest problem, as manifolds appear inside them and the charge capacity decreases. Once this capacity drops to 70 or 60% the battery starts doing strange things and dies. Now, a group of researchers has managed to end that premature death of the batteries.
Usually the current battery starts to have problems after 500 charge cycles, which is about two years if we used up for the equivalent of a full battery every year. Cell phones contain bigger and bigger batteries, so we charge them less, and they can last more than four years with 80% more capacity than the original. Nevertheless, a group of researchers was able to confirm that a battery with 1735 charge cycles maintains 95% of its initial capacity.
Batteries consist of two electrodes: the anode and the cathode. Electrons move from one to the other depending on whether the battery is being charged or discharged. To facilitate transportation, a material known as a binder is used. These bonds are made of polyvinylidene fluoride (PVDF), and this is the material the researchers changed.
Specifically, researchers at the University of Japan have created a binder of a copolymer called bis-imino-acenaphthenequinone-paraphenylene (BP). With this material, not only has the battery improved its impressive performance, but the battery has also maintained its capacity after many battery charge cycles.
BP material provides greater mechanical stability and better adhesion to the anode and current collector. It also has better conductivity than PVDF, is finer and does not interact easily with the electrolyte, which helps reduce the presence of dendrites. Images captured at the microscopic level show only small cracks after 1,735 charge cycles, compared to large cracks in PVDF after only 500 cycles.
Despite the progress in this step, it still requires some work before we can see it in the devices we use every day, but researchers say the system is completely commercially viable, and that they hope to see it in the market soon.
