It sucks, but there isn't much traffic on this board these days.
The analog pin on the ESP8266 chip has a maximum input of only one volt. Look at the schematic diagram of the WeMos board you're using. For example, on the D1Mini schematic we see that WeMos feeds the input from the analog input pin (A0) into a voltage divider consisting of a 220K resistor and a 100K resistor. The analog input to the chip is taken at the junction of the two resistors so a 3.2V input will divide down to 1 volt at the chip's input (the maximum allowed).
I'm no engineer, but I would think that if you added 180K of resistance to the D1 Mini's A0 pin, a full 5V would divide down to 1V, but I don't know if this is within the input impedance specs of the A/D converter.