Why Aren't We Using Batteries That Last 10 Times Longer? Elon Musk Responds

When id Software co-founder John Carmack discussed electric vehicle battery materials on Twitter in August 2022, none other than Tesla, Inc. TSLA CEO Elon Musk chimed in with his view.

Carmack, a computer programmer and video-game developer, said when he looks at electronics with weakening batteries, he wonders about the potential of bulkier lithium iron phosphate (LFP) batteries. These have 40% less energy density but 10 times the lifespan, he noted.

Energy density is the amount of energy in a given mass, and in a battery, it is the measure of the amount of energy that a battery contains in relation to its weight. LFP batteries are supposed to have about 15-25% less energy density than alternatives.

Carmack pointed out that there isn’t much demand for 10-year lifespan consumer electronics. “Of course, easily replaceable batteries can also address the problem!” he added.

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In reply, Musk said high cycle life is possible with nickel cathode if optimizing for that purpose. Adding silicon to the anode, primarily carbon anode, improves energy density, and reduces cycle life, due to large volumetric changes during charge/discharge, he added.

Similarly high cycle life with nickel cathode is possible if optimizing for that.

Adding silicon to (primarily carbon) anode, which improves energy density, reduces cycle life, due to large volumetric changes during charge/discharge.

— Elon Musk (@elonmusk) August 26, 2022

Lithium-ion is the commonly used chemistry in EV batteries, although most EV makers have started using LFP batteries, given their cost competitiveness and longer life.

Originally published on Aug. 28, 2022.

Photo: Created with an image from TED Conference on flickr