Write SQL query to solve given problem: What is the average rental rate of sci-fi film titles?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT AVG(T1.rental_rate) FROM film AS T1 INNER JOIN film_category AS T2 ON T1.film_id = T2.film_id INNER JOIN category AS T3 ON T3.category_id = T2.category_id WHERE T3.`name` = 'Sci-Fi'