Capacitive deionization (CDI) technology has gained wide attention for producing clean and portable water to relieve the pressure on water resource shortages. Faradaic materials are considered to be a promising alternative to traditional carbon materials storing charges in the electrical double layers (EDL) that have limitations due to co-ion repulsion. Herein, we have synthesized High-entropy Prussian blue analogues (HEPBA) with the chelation of citrate using a simple one-step hydrothermal method to control their size, crystallinity and composition. The optimized HEPBA-based electrodes used in half-cells show a high specific capacity of similar to 283 F g(-1) at 1 mV s(-1). A high salt adsorption capacity of 36.8 mg g(-1) stable for the 50 cycles tested here was reached in the membrane-free desalination cell based on HEPBA and Ag@C electrodes. This architecture overcomes the typical limitations of low adsorption capacity and co-ion repulsion, enabling efficient operation without the need for an ion-exchange membrane. The improved salt-adsorption capacity is due to the high optimized crystallinity of the HEPBA material and maintenance of the configurational entropy. A series of ex-situ experiments revealed that the desalination and regeneration processes were governed by the redox of the Fe3+/Fe2+ couple, Mn3+/Mn2+ couple, Co3+/Co2+ couple and Cu2+/Cu+ couple while the Ni3+/Ni2+ couple was electrochemically inactive for the HEPBA. Electrodes fabricated using this simple one-step process provide a possibility to obtain optimized HEPBAs for real-life applications.