Is the lender entitled to claim the difference resulting from inflation from the borrower?

It is not permissible for the lender to ask the borrower for more than what he lent him, unless the borrower allows it without any precondition from the lender or prior agreement between them. In this case, there is no harm in it, and it falls under the category of beneficence, as the Prophet (peace and blessings be upon him) said: "Indeed, the best of people are those who are best in fulfilling their obligations." As for demanding an increase, it removes the loan from being an act of charity and transforms it into a compensatory contract. Therefore, taking the difference is not permissible.