Get sub category of current category in magento2

You can get sub-category by below code at list.phtml

if($this->getLayer()->getCurrentCategory()):
$subcategories=$this->getLayer()->getCurrentCategory()->getCategories($this->getLayer()->getCurrentCategory()->getId());
    /* count and check the category have any sub category */
    if($subcategories->count()>0){

        foreach($subcategories as $subcategory){
            //echo "<pre>";
            //print_r($subcategory->getData());
            echo $subcategory->getName();
        }

    }else{
        // category does not have any sub category
    }
else:
        // category does not have any sub category

endif;

Edit:

add this code:

<!-- add by amit bera -->
    <?php if($this->getLayer()->getCurrentCategory()):   ?>
        <?php 
        if($subcategories->count()>0){

            foreach($subcategories as $subcategory){
                //echo "<pre>";
                //print_r($subcategory->getData());
                echo $subcategory->getName();
            }

        }   
        ?>
    <?php endif ?>

just after <?php if (!$_productCollection->count()): ?>

and

add below code:

<!-- add by amit bera -->
    <?php if($this->getLayer()->getCurrentCategory()):   ?>
        <?php 
        if($subcategories->count()>0){

            foreach($subcategories as $subcategory){
                //echo "<pre>";
                //print_r($subcategory->getData());
                echo $subcategory->getName();
            }

        }   
        ?>
    <?php endif ?>

just after <?php $pos = $block->getPositioned(); ?>

Get source code at http://codepad.org/VwvnFZge

Get subcategory of current category

<?php
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$category = $objectManager->get('Magento\Framework\Registry')->registry('current_category');//get current category
$subcats = $category->getChildrenCategories();
$_helper = $this->helper('Magento\Catalog\Helper\Output');
?>
<ul class="sub-cat">
    <?php
    foreach ($subcats as $subcat) {
            $_category = $objectManager->create('Magento\Catalog\Model\Category')->load($subcat->getId());
            $_outputhelper = $this->helper('Magento\Catalog\Helper\Output');
            $subcaturl = $subcat->getUrl();            
            $_imgHtml = '';
            if ($_imgUrl = $_category->getImageUrl()) {
                $_imgHtml = '<img src="' . $_imgUrl . '" />';
                $_imgHtml = $_outputhelper->categoryAttribute($_category, $_imgHtml, 'image');
                /* @escapeNotVerified */
                echo '<li><a href="' . $subcaturl . '" title="' . $subcat->getName() . '">' . $_imgHtml . '</a></li>';
            }

    } ?>
</ul>