AFAIK, only the latest ADE desktop version (4.x) supports
CJK text, but only in ePub3 files. If you export your book with the Sigil
ePub3 output plugin, the Chinese text will display fine with ADE 4.x. However, most dedicated eInk readers come with older versions. If you want to achieve full backwards compatibility, you'll have to convert the Chinese words to SVG images or recommend that the reader use alternative apps, for example,
Gitden reader.