Fore more than 2 hours capacity, batteries are expensive than most other and cost keeps increasing as more hours of capacity needed. Without gas or coal to burn when 1hr battery capacity runs out, battery storage is expensive.
It's simple power vs energy equations. Let's say you need to supply steady 1MW to town for 1hr, 2hr or 10hr. This needs total of 1MWh 2Mwh or 10Mwh respectively. Let's say battery would cost $200/kwh, then this would cost 200k, 400k or 2M resp. Battery storage is generally used for less than 2hr duration currently where they are price competitive. For the rest, either gas peaker, coal or hydro is used.