Yep. That's the one I use to power R44 and my other non hand-held gear these days (DR-680, F8, V3). Will run the R-44 on its own longer than you'll likely need, but nice to have the extra capacity, for external preamp if you want, charge phone if you want, or if only to not over-discharge the battery overly far to maximize its life.
You can probably get along fine with one of the smaller Talentcells which are half the thickness of that one for typical concerts. I've not used those but they are about the same size as the old DVD batteries if that fits better in your bag (although turned 90 degrees as the ports, meter and power switch are on the short side of the Talentcell vs the long side of the DVD battery.