Figure 2

Power density measurement curves. (a) Instantaneous voltage measurement as a function of time for a mixing solution of NaCl and CaCl\(_2\) of different fractions. A load resistor of 10 \(\Omega \) is connected to the capacitive cell. The voltage drop on the load resistor \(E_{load}\) is measured by a potentiostat. As the solution reversal is realized for a fixed period \(T_s\) = 45 s, an alternating electrical signal is measured. (b) The instantaneous power density P dissipated on the load resistor corresponding to the measurement in (a) for a series of mixing fractions. (c) The temporal averaged power density \(P_{gross}\) as a function of load resistance for divalent ion mixing of NaCl and CaCl\(_2\) for a salinity ratio of 30. The solid lines represent the theoretical prediction based on the R-C equivalent circuit. The dots represent the experimental data obtained for a capacitive salinity gradient cell. (d) The temporal averaged power density \(P_{gross}\) as a function of load resistance for divalent ion mixing of NaCl and MgCl\(_2\) for a salinity ratio of 30. The number presented in the legend corresponds to the molar fraction of NaCl.