How do I retrieve the slug of the current page?

I am trying to retrieve the slug of the current WordPress page outside the loop. The title of the page returns with wp_title (), but how can I get the slug?

<li>
  <a href="https://wordpress.stackexchange.com/slug-of-current-page/">
    <?php wp_title('', true); ?>
  </a>
</li>

Use the global variable $post:

<?php 
    global $post;
    $post_slug = $post->post_name;
?>