As the battery is a single cell 3.6v, 8700mA lithium ion, ideally we want to charge one at the same input voltage, however the battery protection circuit built into the battery compensates for slightly higher voltage input. The lithium ion cell design is such that best charge rates are performed at less than 1C, with ~0.7C being ideal. The battery protection circuit also limits input when higher charge rates are used by terminating the charge cycle when excess heat from a high charge rate is generated. Higher amperage charge rates generate more heat so the protection circuit will terminate the charge before a battery has been fully charged. Under those conditions a li-on battery will indicate it was fully charged at the end of the charge cycle but will not have reached full capacity.
Most all cell phone and tablet chargers are rated 2A or less, which is less than 0.7C, and work just fine for performing a faster charge than the factory charger.