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Scientists develop durable and safe Li-ion battery

As a solution to the problem, the scientists have offered a different crystal structure for the cathode material

Apr 18, 2017
An international team of scientists featuring researchers from Russia’s Skoltech (the university founded by the Skolkovo Foundation and MIT) appears to have found a way of making a storage battery, including that for a smartphone, much more efficient and durable, portal Naked-science.ru reported.

The researchers are said to have been able to change the crystal lattice in the Li-ion battery cathode to boost its efficacy and longevity considerably without compromising safety. The study has been published in English in Nature Materials.

Lithium-ion batteries are used widely across electronics in portable products such as laptops, tablets, mobile phones and photo cameras. Lithium is the charge carrier; when the battery is charging, Li ions leave the crystal lattice of a transition metal (d-metal)’s oxide which can change its oxidation level. In modern batteries, a layered cobalt/lithium oxide structure is typically used.

The number of recharging cycles and capacity (the amount of lithium that leaves the crystal lattice in charging and returns in discharging) are two main characteristics of a Li-ion battery. The problem is, however, that no more than 60% of lithium typically leaves the cathode structure. Otherwise the likelihood of an explosion and fire would grow dramatically. Recharging cycles are not endless, either; energy contained in charges batteries decreases with time.

As a solution to the problem, the scientists have offered a different crystal structure for the cathode material. A classic Li-ion battery has a layered structure, with Li layers alternating with those of oxygen and a transition metal. When lithium abandons its positions, d-metal ions come to replace it. So, lithium basically cannot "return home" as there’s no longer any vacancy for it. That leads to a reduction of battery capacity.

The new concept of a battery structure calls for a shift of layers between one another, thus giving the battery a framework structure that can work in a much more stable manner, losing almost no energy at all. That is expected to help extract lithium from it in its entirety during charging without any risk of fire.