Inspiron 13 7000 replacement battery source

My 2.5 year old Dell Inspiron 13 7000 needs a new battery. Dell official options are to mail the computer in and pay a fee to have it replaced, but I can't be without the computer for a week. The other official option is to purchase an external battery charger to plug in, which makes no sense (I can just use the plug). Can anyone recommend a reputable source for a replacement internal battery that I can install myself? This is my 5th Dell laptop I purchased out of 6 total in the last 22 years, and I have never not been able to purchase a replacement internal battery directly from Dell and do it myself. This is also the earliest (soonest) amount of time I have had a laptop battery fail. Why is this?