Take your average battery for any electronic device: it lasts for x amount of years, and you can do other things while it is being charged for x amount of minutes or hours. Now remove those years, and remove those minutes and hours of charge-time. What you have is, essentially, a Vanadium Redox Battery.
Referred to as a VRB for short (or "Vanadium Redox Flow Battery" for an even longer name), these batteries are slowly gaining popularity because of their main selling point: they don't lose capacity over time either when idle or when being charged/discharged. In most batteries, the chemical reaction that takes place will erode substances in the battery, or some of the chemicals will be permanently lost via consumption. Since no chemical reaction takes place in VRBs, that possibility of substance-erosion or consumption is eliminated, thus the no-capacity-loss trait. And, also thanks to the battery's nature, the time it takes to charge a device using these batteries is extremely shortened, meaning they can charge products almost instantly (well, in comparison to how long it takes products to charge currently).
Another selling point of VRBs are part of its method of creation: Vanadium itself can be made as a by-product of steel smelter slag. With steel production rising in recent years (and prospects of continued increase in production), the act of creating Vanadium wouldn't exactly be out-of-the-way for companies.
Of course, there's a downside. The average energy density of a VRB is lower than that of most rechargeable batteries (at that size). It's likely that, given time, research, and a bit of tinkering, the average energy density of a VRB will increase over the upcoming years.
Another fun fact: as with most batteries, the bigger the size, the bigger the output. This holds true for VRBs, since they can make use of "storage tanks", which are essentially large holding areas containing electrolytes that can be used in conjunction with the VRB. Think of it as a battery pack...for your battery pack. (I wonder when our battery packs' battery packs will have battery packs. Confusing, much?)
While current use of VRBs are limited for now, they definitely have potential and should at least be interesting to watch over the next few years.
Sources: Rocky Mountain Resources and The University of South Wales