A research team at Argonne National Laboratory introduces a redox-active intermediate layer into a lithium-sulfur (Li-S) battery, dramatically increasing energy density and cycle life, which have been challenges for commercialization. succeeded in
The research results were published in the journal Nature Communications on August 8, 2022.
Currently, lithium-ion batteries are used in various places such as mobile phones and electric vehicles. However, lithium-ion batteries also have drawbacks such as short lifespan, easy overheating, and difficult raw material supply. As an alternative battery, the Li-S battery, which has a much higher theoretical energy density, is rich in sulfur as a raw material, and is inexpensive, is expected and is under development.
A Li-S battery has a structure in which an organic electrolyte is sandwiched between a positive electrode containing sulfur and a negative electrode made of lithium metal. However, due to the shuttle effect in which the polysulfide, which is a reaction intermediate of the positive electrode, dissolves in the electrolyte and moves to the negative electrode, self-discharge progresses and the charge rate decreases, and the battery life is shortened.
To prevent the shuttle effect of polysulfide, previous studies have attempted to place a redox-inert protective interlayer between the positive and negative electrodes. However, the protective interlayer makes the battery even heavier, reduces the energy storage capacity per unit weight of the battery, and cannot sufficiently suppress the shuttle effect, which has been a major barrier to the practical application of Li-S batteries. .
The research team developed a porous sulfur-containing interlayer with redox activity and introduced it into Li-S batteries. The battery exhibited an initial capacity about three times higher than that with an inert interlayer, and retained 64% of its initial capacity over 700 charge-discharge cycles. It was found that the oxidation-reduction active interlayer protects the lithium negative electrode, electrochemically reactivates the polysulfide dissolved in the electrolyte, and increases the battery capacity.
In the future, the research team hopes to improve the performance of Li-S batteries by further developing interlayer technology with redox activity, making the interlayer thinner and lighter, and promoting practical application.
Related information
Development of high-energy non-aqueous lithium-sulfur batteries via redox-active interlayer strategy | Nature Communications
Lithium-sulfur batteries are one step closer to powering the future | Argonne National Laboratory
