Large marine batteries are a special case of their own, because they need maximum storage density. This suggests using high-powered lithium-carbon dioxide batteries for marine propulsion. On paper at least, these could deliver far superior energy density to lithium-ion, according to The Royal Institution of Naval Architects.
Lithium-Carbon Dioxide Is a Relatively New Chemistry
We are speaking of a fairly novel battery type here, that uses carbon dioxide as its cathode and lithium as its anode. The cathode is thus a super-abundantly inexpensive material, which could drive battery costs down. But there are other advantages too.
Lithium-carbon dioxide batteries boast superior energy density by volume, compared to other high-energy batteries. This could also make them ideal for electric vehicles, and small aircraft where space is a premium.
We understand that researchers at University of Illinois in Chicago, have developed a novel lithium-carbon material that improves the chemistry further. The Illinois team have built a prototype version of this, that managed 500 consecutive charge / discharge cycles.
Quite incredibly, the team are imagining a future where carbon dioxide and lithium deliver seven times more energy than the best batteries available today.

The Road Ahead For These Intriguing Batteries.
The Royal Institution of Architects that we link to below, confirms that other agencies are also exploring lithium carbon-dioxide chemistry. There, researchers are focusing on improving cathode density further, and replacing liquid and gel electrolytes with solid options.
There are, however, a number of drawbacks to this technology, preventing it from becoming commercially viable. Here we think particularly of the limited number of charge cycles before battery performance begins to degrade. There is also a potential disadvantage of the two electrodes generating hazardous heat.
And so, for now at least, lithium-carbon dioxide batteries seem destined to remain a theoretical concept for a while longer. The chemistry is none the less interesting, and bound to continue occupying the minds of scientists.
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