How can I use I-797 with expired I-551 stamp as travel documents and work authorization?

Yes you can. However, make sure you keep the new renewal with you all the time to facilitate easy proof if needed for leaving and re-entering purposes.

The receipt is valid for 18 months from the expiration date of your green card. If you travel after that, you will need further passport stamps.

Read the notice carefully. It is merely a re-issuance of the notice you already got. It expires 18 months from the date of issuance and is almost certainly already expired. You will need to get a new ADIT or temporary green card stamp and now they want emergent reasons.

Yes, the form I-797 receipt notice generally serves as evidence of continue status for 18 months past the expiration date on the permanent resident card of the petitioner. During this extension, you are authorized to work and travel.

The new 18-month extension stamps contain language indicating that the extension is from the expiration date of your green card, which expired four years ago. Therefore, I believe the extension notices are worthless because they may lead a CBP officer at the port of entry to believe that the conditional status expired or is no longer valid. I am counseling my clients in the United States to call the USCIS Contact Center and request InfoPass appointments to obtain new I-551 extension stamps. The results are hit-or-miss due to inconsistent USCIS policy and handling of such requests. Persistence is needed. For clients who are abroad when their stamps or extension receipts expire and who have been absent for more than six months but less than one year, I am advising them to obtain I-131A transportation/boarding letters so they may board their return flights to the United States.

Generally, you need the actual expired green card. Check with an attorney before traveling.

Yes, you can.