 EEStor coats its 0.64 micrometer (average size) CMBT particles with 10 nm aluminum oxide (6% by volume) and immerses them in 6% PET plastic by volume, giving 88% CMBT.The patent claims the aluminum oxide coating and PET matrix reduce the net permittivity to 88% of the CMBT permittivity.The Philips patent did not use either aluminum oxide or PET.