Energy density of "heat storage ceramic" vs. NMC li-ion batteries

Question

I was intrigued to read about so-called "heat storage ceramic" and was wondering how the energy stored in such way compares to energy stored in a NMC Li-Ion battery, if the latter is used to generate heat (the article lists it a 230kJ L^-1). I know it is not an apples-to-apples comparison, but I am curious about any ballpark assessment, especially in terms of energy stored per kg.

The main reason for my interest is potential use in electric vehicles in cold climates. I drive an EV in Quebec, and I know that when the temperature is significantly below freezing, I can expect to spend 5-7KWh per 100km of driving simply to heat the interior. If energy density of "heat-storage ceramic" is significantly higher per weight or volume, it could make sense to install heat storage "batteries" alongside electrical batteries.

Answer 1

The energy density of lithium Ion batteries is between 900 kJ/L and 2430 kJ/L according to Wikipedia. This is at least a factor of 4 higher than the energy density you give for the heat storage ceramic so no gains in terms of space.

Some example ceramics have a specific gravity ranging from 2.5 kg/L to 6.0 kg/L. At the lower end, the heat storage ceramics will have a specific energy of 92 kJ/kg while the lithium ion batteries range between 100 and 265. So, if the heat storage ceramics have a very low specific gravity, then you might save a little bit of weight over low density lithium ion batteries, but the gains won't be substantial.