The 接続詞（せつぞくし） (conjunction) それに
is regularly considered to be one word in Japanese, but is more correctly just a combination of the 代名詞（だいめいし） (substitute noun) それ
, and the 格助詞（かくじょし） (case-marking particle) に
The thing that それ
is ‘substituting’ for is the entire clause/sentence that came before it, while に
highlights that extra information is about to be added. In this way, it translates to ‘and to that’, or ‘and on that’, where ‘that’ is the previous information. Often, it is translated simply as ‘moreover’, ‘in addition’, or ‘and’.
In addition, he doesn't do house chores either, right?
Lisa’s company doesn't have overtime work. What’s more, her salary is good too.
is ‘adding’ information with に
, the (B) information itself must be something that would logically happen ‘in addition to (A)’, or ‘as a result of (A)’. Therefore, それに
will highlight something that has either all positive, or all negative connotations. Never both.
Yesterday, I picked up 5 thousand yen on the street, and in addition to that I won a car in the lottery. (Natural Japanese, as both events are positive)
Recently, it has been raining a lot, and in addition to that the wind has been strong. I'm sad that I can't go outside. (Natural Japanese, as both events are negative)
I went to get a massage this morning, and moreover I also got a speeding ticket. (Unnatural Japanese, as one event is positive, while the other is negative)