Lithium-ion batteries are everywhere: in your smartphone, in your camera, … These types of rechargeable batteries are great for any portable electronics as it has a small memory effect and low self-discharge. However, that doesn’t mean that it can’t be improved. In 2007, Fu et al. tested three-dimensionally ordered mesoporous titania microparticles as “new” anode material. Why titania? I don’t know. Fact is, “conventional Li-storage materials suffer serious capacity loss when they are charged/discharged at a high rate. Polarization caused by slow diffusion of lithium ions and electrons in active materials is one challenging problem.“ As far as I understand it (and please my dear reader correct me if I am wrong) that means, that the lithium ions need a certain time to travel between between the electrodes. Therefore, if you are charging and discharging faster than the lithium ions need to travel from the one electrode to the other, this results in a capacity loss. Normally the anode in a lithium ion battery is made of graphitic layers. Between the stacked layers the lithium ions are normally stored in the charging process. While discharging, the lithium ions travel to the cathode. So summing up, the traveling time between the anode and the cathode (and the other way around) is the reason for polarization. However, “previous studies showed that electrode materials with three-dimensionally (3D) ordered mesoporous structure could decrease the polarization and enhance the performance at high rates”. That means that if the electrode material has a 3d structure with “pores” instead of the graphitic layers, the lithium ions can travel faster and so the polarization is decreased. Therefore, Fu et al. created a 3D ordered mesoporous structure out of titania and used it as anode. Indeed, the 3d structure was “beneficial to the diffusion of lithium ions” which reduced the capacity loss. So 3d is better than 2d… at least regarding the structure of the anode material in lithium ion batteries… (for movies I still prefer 2d… but this is maybe a question of taste). "Preparation and characterization of three-dimensionally ordered mesoporous titania microparticles as anode material for lithium ion battery."
Fu et al. Electrochemistry Communications 9.8 (2007): 2140-2144.
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