Dell Precision 5520 Battery Replacement

Hello,

I'm looking for a battery replacement for my Dell Precision 5520.  The current battery lasts about two hours on a full charge when it should last around eleven.  I'm wondering if I should buy this battery from Dell's official website (https://www.dell.com/en-us/work/shop/dell-97-whr-6-cell-lithium-ion-battery/apd/451-bcgi/pc-accessories#polaris-pd), or this battery from Laptop Battery Express (https://www.laptopbatteryexpress.com/Long-Run-Battery-Dell-Precision-15-5510-p/dell-6gtpy.htm?CartID=1).  However, under the compatibility section for the battery from Dell it only says it's compatible with the Dell Precision 7530 and 7730, is their a different battery from Dell I should be looking at that is compatible with the Dell Precision 5520?  Should I just buy the battery from Laptop Battery Express?