Zikr & Dua

Reciting "​​La ilaha illallah" 70,000 times

Q: Is it an innovation to recite Kalima "​​La ilaha illallah" ​​70,000 times with hope that the deceased will be saved from the punishment of ​​grave and ​​Hell fire? I really wish to know that and is thinking of doing this for my mother who died on 5th July 2017. Help me in this regard and please pray for the forgiveness of my mother and all the muslims.