A Strategy for Power Density Amelioration of Capacitive Reverse Electrodialysis Systems with a Single Membrane

Blue energy refers to the osmotic energy released while combining solutions of different salinity. Recently, single-membrane-based capacitive reverse electrodialysis cells were developed for blue energy harvesting. The performance of these cells is limited by the low ion-electron flux transfer efficiency of the capacitive electrodes in the current operating regimes. To optimize it, we point out an original boosting strategy of using a secondary voltage source E₀ placed in series with the capacitive concentration cell. The net recovered power is defined as the difference between the power dissipated in the load resistor and the power supplied by the secondary voltage. Experimental results indicate a maximum power density of 5.26 W·m^-2 (where the salinity difference is 0.17 and 5.13 M), which corresponds to a 59.8% increase compared with its power density of 3.29 W·m^-2 without boosting strategy. A good agreement on power density is reached for theoretical simulations and experimental results. Influential factors are systematically studied to further reveal the boosting strategy.