As previously reported here, NASA internal discussions seemed to indicate that at one point they had acquired EEStor technology. According to follow up correspondence today between a FOIA administrator and Mr. Ambrose, NASA did not ever purchase EEStor technology as Ambrose seemed to indicate in his released email.
The NASA information on EEStor is still under investigation and it would appear that there is definitely more to learn. For example, the six SBIR proposals EEStor supposedly submitted in 2002. Proposals, I can't seem to find in the online NASA database.