Xiaomi is running a temporary battery replacement service for 21 Xiaomi and Redmi-branded smartphones. The program will operate from July 1 to July 7 and users will only have to pay 49 yuan (US$7) to take advantage of the scheme. The Xiaomi Mi 9, which has been criticized for its poor battery life, is included as is the popular Redmi Note 7.
https://www.notebookcheck.net/Xiaomi-announces-49-yuan-US-7-battery-replacement-service-covering-21-smartphones-including-the-Xiaomi-Mi-9-and-Redmi-Note-7.477594.0.html