Razor Phone 2 Battery Problems

Hi the last couple of weeks i have noticed that my razor phone 2 has started to shutdown after reaching about 40% battery life and wont turn back on till it gets charged. I believe this is a common problem in a lot of phones with the batteries made to die, but i have had the phone about a year and a half and wouldnt expect the battery to be this bad this quick.
Is there anything i can do myself to fix this?
I have done all the usual clear cache, used adaptive battery and i have my brightness less than half all the time now