How can I make the introduction of a paper more "scientific" and less "popular"?
This is a common issue when inexperienced people write their first papers. It's tempting to write down everything that went into your personal understanding of a subject, rather than just starting from what's known and focusing on the new things you did.

Imagine if you looked up a recipe for a pie and the first 80% of it detailed the history of wheat cultivation, how wheat is made into flour, the way the tablespoon and teaspoon were defined as units of measure, statistics on the average consumption and enjoyment of pie throughout the 20th century, and so on. Imagine if you looked up the text of a new regulation and it started with "This law could be passed in our state legislature because, in 1773, the Boston tea party...". Imagine if a car repair manual started with the history of the wheel.

It's important to tell the public why science is important and why your studies make sense, but a paper isn't the place to do it. It's also not the place to give a full exposition of every technique you used. If you must, just put references to review articles or textbooks.