Style wp_list_categories

My suggestion.

$categories = get_the_category();
$output="";
if($categories) {
    $output = "<ul>";
    foreach($categories as $category) {
        $output .= '<li><div class="btn-standard"><a href="'.get_category_link( $category->term_id ).'" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '">'.$category->cat_name.'</a></div></li>';
    }
    $output .= "</ul>";
}
echo $output;

You can check Codex for more reference.