Hi,
I'd recommend getting a ccTLD (.cn) and hosting in China or Hong Kong. Also localizing your website with the help of native professionals.
Pros: This is the clearest sign to Baidu (The predominant search engine in China) and to all search engines in general.
Cons: The domain authority of the new site will be completely independent of the current site and it might be expensive
Now, if you wish to use a gTLD and put the Chinese version of the site in a subdirectory. That's fine too. Just remember to add the Hreflang tags.
Pros: Less expensive
Cons: Chinese search engines and internet users favorite sites that are hosted locally.