There are continuous research and experiments underway to find new and better batteries that are sustainable, safe and stable. In one such attempt, researchers discovered stable and safe lithium-sulfide battery that can be folded and even cut into half.
A research team from the University of Electronics Science and Technology of China successfully created transition-metal sulfide-based lithium batteries. The researchers coated iron sulfide cathodes in polymers resulting in stable cycling and high safety. Then, after 300 cycles, the lithium carbide iron disulfide pouch cell retained around 72.0% capacity. Moreover, this lithium-sulfur (Li-S) after 100 cycles, there was no capacity degradation.
Surprisingly, scientists were able to fold and cut off one of the battery pouch cells. According to the researchers, it proves that the cell is highly safe for practical applications.

Advantages: Easily available with high energy density and low cost are advantages of conversion-type transition-metal sulfides (MSc). These qualities make them promising cathodes for lithium-ion batteries (LIBs).
Challenges: MSx has stability issues under high temperatures due to polysulfide shutting. It also faces substantial volume expansion and sluggish reaction kinetics.
Solutions: The group previously proposed the use of a carbonate-based electrolyte to separate 2 electrodes, an iron sulfide cathode along with a lithium metal-containing anode.
However, this solution resulted in another problem.
Problem: The researchers mentioned that the incompatibility of MSx with carbonate-based electrolytes is a major challenge for this type of battery chemistry. Polysulfides react with carbonate solvents which form precipitates on the surface of the electrode. This leads to the creation of a barrier for charge transfer, causing electrode blockage and battery failure.
Solution: The iron sulfide cathodes were coated with different polymers. This reduced the corrosion without affecting or reducing functionality and rechargeability. Polyacrylic acid (PAA), polyethylene oxide (PEO), and polyacrylamide (PAM) were specifically used as they all contain functional groups with a chelation effect.
In another research, an eco-friendly battery production from all-dry synthesis and rock salt oxide was discovered.

The report mentions, “The chelation effect is based on the coordination of lone pair electrons on oxygen or nitrogen and empty orbitals of multivalent transition metals.”
Electrochemical Performance Tests show that PAA performed best by retaining the discharge capacity of the electrode after 300 charge-discharge cycles.
After this, they added a PAA-coated iron sulfide (FeS2) cathode into the stable and safe Lithium-sulfide battery prototype design. The design also has a lithium metal foil as an ion source and a lithium carbide (LiC6) anode. Further, the test also showed that there was no capacity degradation after 100 cycles and even when the cell was folded or cut.
The researchers also stated, “LiC6||MoS6 full cells demonstrated excellent cycling stability for 300 cycles with the same high capacity as the half-cell (Li||MoS6), and the same situation also occurred in LiC6||VS4,” they stated.