Efficiency (percent for percent) can buy you all the advantages of higher energy density, but with higher charge speed (ie miles per charge minute, for a given wattage), lower charge cost, cheaper battery (fewer kWhs), etc. So really, you wouldn’t want to sacrifice much efficiency to get greater energy density. You really want BOTH. A Lucid Air with this kind of battery would have greater range than a lot of gas cars; a fantastic road trip car. In fact, you could go basically a full day’s driving (11-12hours) without charging, then charge overnight with a beefy L2 charger (typically a lot cheaper than fast charging) and never have to actually stop during the day for charging.