Duplicate keys detected: '0'原因及解决方法

<div class="info" v-for="(item, index) in currentFriend.content" :key="index">
    <div class="d1">
            <p v-text="item.time" class="timeBox"></p>
    </div>
</div>
<div class="info2" v-for="(item, index) in currentFriend.content" :key="'index">
    <div class="d2">
          <p v-text="item.time" class="timeBox"></p>
      </div>
</div>

<div class="info2" v-for="(item, index) in currentFriend.content" :key="'info2-'+index">
    <div class="d2">
          <p v-text="item.time" class="timeBox"></p>
      </div>
</div>