Greatest volumetric heat capacity

Question

Is there any substance with bigger volumetric heat capacity than water? According to this table water has the biggest known VHC. But I can't believe that in the 21. century we have no special material with larger VHC.

Answer 1

Here is a thesis that details construction and characterization of thin films with large volumetric heat capacities (some nearing $6\ MJ\cdot m^{-3}K^{-1}$):

Volumetric heat capacity enhancement in ultrathin fluorocarbon polymers for capacitive thermal management