Low Resistance Cation-Exchange Membrane (CEM) for Membrane Capacitive Deionization (MCDI), CMCDILRCEM

In Membrane Capacitive Deionization (MCDI), placing ion-exchange membranes directly in front of the porous carbon electrodes (an anion-exchange membrane [AEM] at the anode and a cation-exchange membrane [CEM] at the cathode) prevents co-ion expulsion and significantly boosts charge efficiency and salt removal capacity. However, because MCDI relies on transient electrical cycling (alternating polarization and regeneration), ohmic resistance losses across the CEM represent one of the primary bottlenecks limiting energy efficiency and maximum salt adsorption rate (SAR).

To minimize voltage drop and energetic penalty during rapid charging cycles, high-performance CEMs require specific electrochemical parameters: (1) Low Area Electrical Resistance (R_Ω): Ideally < 1.0 Ω*cm2 (often approaching 0.5 - 0.8 Ω*cm2 in 0.1 M NaCl) to prevent excessive ohmic heating and voltage waste. (2) High Ion Exchange Capacity (IEC): Typically 1.2 to 2.0 mmol/g to ensure a high concentration of fixed negative charges (e.g., tethered sulfonate groups -SO3^-) for efficient counter-ion (Na+) transport. (3) Optimized Thickness: Ultra-thin profiles (15-50 um) are heavily favored over traditional thick chlor-alkali membranes to drastically cut down diffusional and electrical resistance paths. (4) High Permeselectivity / Donnan Exclusion: > 95% to prevent co-ion (Cl-) leakage, ensuring that charge efficiency remains near unity. (5) Moderate Water Uptake: Balanced swelling (15% - 30%) to facilitate rapid hydration-shell ion mobility without sacrificing dimensional stability or mechanical strength during repeated volume expansion/contraction of the underlying carbon electrodes.

Part Number	CMCDILRCEM (C-MCDI-LRCEM)
Working Mechanism
Membrane Thickness (Dry)	~50 um
Area Resistance	≤2.7 Ω*cm2 (0.5 M NaCl, 25°C)
Selectivity	≥96%
pH Range	1-12
Burst Intensity	≥0.25 MPa
Water Penetration Rate	≤ 0.1 mL/h*cm2*MPa
Thermal Stability	≤ 50 °C
Package Grade	L20-80cm*W20-40cm/pcs/pack

Reference: 

1. H. Yook, et al., Effects of characteristics of cation exchange membrane on desalination performance of membrane capacitive deionization, Desalination, 2019, 458, 116-121
2. D. H. Kim, et al., Capacitive deionization employing pore-filled cation-exchange membranes for energy-efficient removal of multivalent cations, Electrochimica Acta, 2019, 295, 164-172