Could EMS (Electric Muscle Stimulation​) Xbody help with repairing diastasis recti?

EMS can build muscle, but not enough to repair distastis recti.  If there is minimal skin laxity, repair can be accomplished through a small incision.  This would involve dissecting a small path overlying the rectus fascia and sewing the fascia together to correct diastasis. From your description of a big bulge and some skin, it's likely that a TT with plication performed by a board certified PS is your best option.

While some treatments such as EMS can give some improvement in some patients, the only definitive treatment is tummy tuck with diastasis repair. 

Dear baharehb,diastasis recti can be repaired only during surgery when sutures are used to tighten the diastasis recti. If you are considering a surgery, I would suggest you to consult a board-certified plastic surgeon. Only after a thorough examination you will get more information and recommendations.Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Thanks so much for sharing your question and concerns.
I admittedly do not have any experience or insight into the EMS system you mention. My experience is that direct plicatation, or suture reapproximation, of the abdominal muscles is a safe and appropriate method for diastasis repair as part of the Modern Mommy Makeover. The procedure can be done through a tummy tuck incision to keep the scar relatively well hidden, and most patients do very well with respect to postoperative recovery and regaining shape and strength in their core. 
I recommend speaking with a Plastic Surgeon to discuss whether this method of repair is right for you. Best of luck to you! 
Peter A. Felice, MD