Yes, th:attr to the rescue Thymeleaf documentation – Setting attribute values.
For your scenario, this should do the job:
<div th:attr="data-el_id=${element.getId()}">
XML rules do not allow you to set an attribute twice in a tag, so you can’t have more than one th:attr in the same element.
Note: If you want more that one attribute, separate the different attributes by comma:
<div th:attr="data-id=${element.getId()},data-name=${element.getName()}">