LibreOffice can Export to EPUB up to 3.0, but EPUB 3.1 is already published in January 2017, so LibreOffice can be improved to give support. See the following changes from 3.0:
Steps to Reproduce:
User Profile Reset: No
Version: 220.127.116.11 (x64)
CPU 线程：4; 操作系统：Windows 10.0; UI 渲染：默认;
区域语言：zh-CN (zh_CN); Calc: group
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0
enhancement request. status NEW.
Forget it. EPUB 3.1 is about to be rescinded by the EPUB3 Community Group at W3C in favor of a 3.0.2, based on 3.0.1, and preserving some good bits from 3.1.
Keep the bug open for the time being, but be ready for a WONTFIX.
So I decided to close this in favor of bug 115406.