What are some advantages of Li-ion batteries?

Compared to the other high-quality rechargeable battery technologies (nickel-cadmium or nickel-metal-hydride), Li-ion batteries have a number of advantages. They have one of the highest energy densities of any battery technology today (100-265 Wh/kg or 250-670 Wh/L). "

So, using that 100-265 Wh/kg as a base figure it would seem that achieving a 500 Wh/kg energy density would double the lithium ion energy density level.

From a 22 February 2023 note originating from the Argonne National Laboratory:

"In past lithium-air designs, the lithium in a lithium metal anode moves through a liquid electrolyte to combine with oxygen during the discharge, yielding lithium peroxide (Li2O2) or superoxide (LiO2) at the cathode. The lithium peroxide or superoxide is then broken back down into its lithium and oxygen components during the charge. This chemical sequence stores and releases energy on demand.

The team’s new solid electrolyte is composed of  a ceramic polymer material made from relatively inexpensive elements in nanoparticle form. This new solid enables chemical reactions that produce lithium oxide (Li2O) on discharge.

“The chemical reaction for lithium superoxide or peroxide only involves one or two electrons stored per oxygen molecule, whereas that for lithium oxide involves four electrons,” said Argonne chemist Rachid Amine. More electrons stored means higher energy density.

The team’s lithium-air design is the first lithium-air battery that has achieved a four-electron reaction at room temperature. It also operates with oxygen supplied by air from the surrounding environment. "

I found the next material from the Argonne Laboratory February article most interesting and most germain to the issue of Energy Density as it relates to the future of Lithium-Air Batteries:

“The lithium-air battery has the highest projected energy density of any battery technology being considered for the next generation of batteries beyond lithium ion.” — Larry Curtiss, Argonne Distinguished Fellow

More importantly, the team’s battery chemistry with the solid electrolyte can potentially boost the energy density by as much as four times above lithium-ion batteries, which translates  into longer driving range.

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Bottom line is that we already have development of a Lithium-Air battery with double the Energy Density of old Lithium Ion batteries and the Argone Laboratory is developing one with 4X that base Energy Density.  

In the words of Colonel Charles E. Stanton (Aide to General J.J. Pershing) spoken on 2 July 2017 at the tomb of the Marquis de Layfayette:  "Layfayette, We Are Here!"

In terms of the Lithium Air Battery innovation:  "Layfayette, We ARE here!"

As for "storage alternative batteries", i.e. stationary batteries, that will be the ballywick of Flow Batteries, not so much, if any, for Lithium Ion or Lithium Air batteries.  JMO.

Okiedo