Nexus 5 bricked...can't mount storage and flash write failure

From last week my phone got stucked at boot(Google logo)
I went to recovery mode-twrp and clicked factory reset..it failed saying that unable to mount storage
And I also tried nexus tool kit
To flast lollipop stock rom
It say flash write failure..
And tried fastboot flash all.bat method also but not works
Please help...me to fix dis...


Sent from my Nexus 5 using Tapatalk