Firstly, the W-Cap was analyzed without applying Ubias to GE ("no bias" state, GE disconnected) by cycling at 5 mV s -1 (optimal cycling rate to ensure high current rectification according to our previous studies.) As a voltage window ±0.7 V was chosen to ensure electrolyte stability even when higher Ubias are applied. In Figure , the CV curves show the typical CAPode shape which can be obtained by cycling the W-Cap without applying any Ubias (disconnected GE) with high current answers under "open" polarization and suppressed currents under "blocked" polarization. As the potential distribution studies reveal, the electrodes show a highly asymmetric behavior depending on the polarization (controlled by CV) of WE and CE (Figure ). Under "open" polarization, the Cmicro and Cmeso electrode are almost symmetrically polarized working in a similar potential range because a comparable potential is required to accumulate the ions in the respective pores (ions can easily enter; high overall capacitance). However, a slight asymmetry between WE and CE can be observed (higher polarization of CE compared to WE) due to the higher capacitance of WE compared to CE like the electrode balancing experiments reveal (discussed in Supporting Information (SI); Figure ) which is in agreement with our former studies. Under "blocked" polarization the potential of the Cmeso electrode (positively polarized) is quasiconstant, varying only in a small range from 0.24 to 0.43 V. In contrast, the Cmicro electrode (negatively polarized) is highly polarized to reach the maximal negative voltage window value of -0.7 V. While the small anions can easily enter Cmeso, Cmicro electrode tries to balance the charges accumulated at Cmeso but large cations cannot enter the pores, due to the sieving effect, leading to an increase in the electrochemical potential to accumulate the large cations on the limited outer surface of Cmicro. A similar behavior can be seen in the galvanostatic charging/discharging (GCD) measurements (Figure ). Under "open" polarization both WE and CE are charging almost linearly, however the CE is more polarized than the WE (potential range WE = 0.5 V; CE = -0.2 V; OCV = 0.29 V) due to a higher capacitance of the WE compared to CE (Figure ). Under "blocking" polarization only a limited charge can be stored as reflected by the fast charge/discharging time in the negative voltage range (42 s under "blocked" and 345 s under "open" polarization at 0.55 µA mm -2 ). In contrast, the GE-CE half system shows a characteristic rectangular CV-curve of a polarization-independent charging and discharging process because both, cations and anions, can easily enter the mesoporous structure of CE and GE (Figure ).