The batteries of Xiaomi smart door locks are generally specially designed and produced, and it is only recommended to use original batteries or officially designated replaceable batteries. Therefore, it is not recommended to use Nanfu batteries for Xiaomi smart door locks, so as not to short circuit, damage the device or cause security problems. If you need to replace the battery, it is recommended to contact Xiaomi's official customer service or authorized maintenance center to obtain the original battery or the officially designated replaceable battery.