- New lithium-carbon dioxide batteries can be fully charged/recharged up to 500 consecutive charge/discharge cycles.
- The battery is made by integrating a unique combination of materials.
Lithium-ion batteries are used in almost all consumer electronics. However, higher electrochemical energy storage systems are required for electrified transportation applications.
In the last few years, beyond lithium-ion battery chemistries (such as rechargeable lithium-carbon dioxide batteries) have drawn much attention because of their higher theoretical energy density.
Such lithium batteries involve carbon dioxide evolution and reduction reactions during charge and discharge on the porous cathode surface. Despite years of studies, the electrochemical reactions of lithium-carbon dioxides batteries remain poorly understood.
One of the biggest problems with these batteries is to obtain reversible formation and decomposition of the multi-component composite and carbon discharge products. This is why, until now, scientists haven’t been able to build a fully rechargeable prototype.
Recently, a research team at the University of Illinois at Chicago demonstrated a design of lithium-carbon dioxide batteries that can be fully recharged up to 500 consecutive charge/discharge cycles.
How Did They Do It?
When these batteries discharge, they produce lithium carbonate along with carbon. The lithium carbonate gets recycled during the charge phase, while carbon remains accumulated on the catalyst, which gradually degrades the battery performance.
The accumulated carbon does three things:
- Blocks the active spots of the catalyst
- Prevents diffusion of carbon dioxide
- Triggers electrolyte decomposition in a charged state
To overcome this problem, researchers used new materials in the battery which enabled recycling of both carbon and lithium carbonate. They utilized nanoflakes of molybdenum disulfide as a cathode catalyst combined with an ionic dimethyl sulfoxide electrolyte.
This combination creates a multicomponent composite product (instead of separate products), substantially increasing the battery cycles. In other words, this unique combination of materials makes lithium-carbon dioxide batteries more efficient with long-lasting cycle life.
The new battery has a cycle life of 500 for a fixed 500 mAh g-1 capacity per cycle, which is far better than the cycling stability of existing lithium-carbon dioxide batteries. In fact, the charge potential shows nearly a 12% increase during 500 cycles, confirming the stable and sustainable performance of the cell during the first 500 consecutive cycles.
This is the first time someone has developed a fully rechargeable carbon-neutral lithium carbon dioxide battery. The impressive cycle life shows that the formation and breaking of complex carbon-oxygen bonds can be used in energy storage systems.
The findings can open new avenues for the development of next-generation energy storage systems using carbon dioxide.