Specification
That sounds about right if this battery is anything to go by.
I assume you are talking about Energy/Mass or Wh/gram. Apparently it is called specific density, whereas Energy Density is measured as Wh/L
Because u say power/weight but measure in Current/Mass. So careful with your units.
Votage: 3.7v
Capacity?1000mA
Continuous Discharge Rating: 1C
Maximum Discharge Rating: 1C
Connector: PH2.0 JST connector
Cable Length: Approx. 70mm
Size: 58x35x5mm
Weight: 22g
(random internet battery.)
Energy/Mass = V * Ah/kg = 3.7 * 1/ 0.022 = 168 Wh/kg
(your battery.)
Energy/Mass = V * Ah/kg = 7.4 * 28 = 207 Wh/kg
Maybe the series cell arrangement is confusing you. This will give the same Wh/kg, a higher voltage but less Ah/kg