No code, but Fatal exception (0): epc1=0x402066ac, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00000000, depc=0x00000000 in Serial Monitor
Three words.  "You Bricked it"
Before you go surfing on the web for days and days, I'm just going to say the module is bricked.  I've been there and found out that you should never use these devices on breadboards and with funky power sources.  There is this chip within the module called eFuse,  which is basically an electronic fuse that's really easy to destroy.  Just use the Arduino YUN or other certified or Chinese clonable modules. Those Italians are smarter than you think. That's probably more reliable because you won't have any power issues or frying issues.

I'm also assuming that you are getting a fatal exception (0) in the Serial Monitor.  In that case, your module's death sentence is officially sealed.  

Congrats. :(