A method for the preparation of electrodes of boron-doped nanocrystalline diamond B-NCD with multi-layer diamond coating, characterised in that it consists of the following steps: a) Preparation of a substrate by subjecting a titanium plate in an ultrasonic bath lasting 5 minutes in acetone, followed by washing in isopropanol and drying under a nitrogen stream; b) Application of a first diamond layer of a thickness of the order of 5-20 nm, containing crystals of the nanodiamond obtained by detonation with a size of 2-15 nm, in the form of a nanodiamond nuclei with density of the nanodiamond nuclei in relation to the substrate surface not lower than 10 10 /cm 2, with the use of a solution containing: 0,25% of nanodiamond with average grain size 10 nm, 0,5% of polyvinyl alcohol and dimethyl sulfoxide as a solvent; c) Application of an adhesive diamond layer in the CVD (Chemical Vapor Deposition) process, wherein the nucleated electrode substrate from step b) is heated up to 500 °C under conditions that a hydrogen rich microwave plasma contains 4% by volume of methane and 5000 ppm by volume of boron supplied as diborane precursor (B 2 H 6), wherein the pressure of 6,7 kPa (50 torr) and the constant flow of hydrogen of 3,34 x 10 -6 m 3 /s (200 sccm) are maintained and the process is carried out for 30 minutes with the use of microwaves at a frequency of 2,45 GHz and with a power of 1300 W; d) Application of a working electrode layer in the CVD (Chemical Vapor Deposition) process, wherein the electrode substrate from step c) is heated up to 700°C under conditions that the hydrogen rich microwave plasma contains 1% by volume of methane and 5000 ppm by volume of boron supplied as diborane precursor (B 2 H 6), wherein the pressure of 6,7 kPa (50 torr) and the constant flow of gas of 5,1 x 10 -6 m 3 /s (300 sccm) are maintained and the process is carried out for 6 hours with the use of microwaves at a frequency of 2,45 GHZ and with the power of 1300 W; e) Hydrogenation of the working layer by heating the electrode obtained from step d) to 700 °C with the presence of a hydrogen rich microwave plasma, the pressure is 5,3 kPa (40 torr) and the constant flow of hydrogen is 5,1 x 10 -6 m 3 /s (300 sccm), wherein the process is carried out for 10 minutes with the use of microwaves at a frequency of 2,45 GHz and with the power of 1300 W. a) Preparation of a substrate by subjecting a titanium plate in an ultrasonic bath lasting 5 minutes in acetone, followed by washing in isopropanol and drying under a nitrogen stream; b) Application of a first diamond layer of a thickness of the order of 5-20 nm, containing crystals of the nanodiamond obtained by detonation with a size of 2-15 nm, in the form of a nanodiamond nuclei with density of the nanodiamond nuclei in relation to the substrate surface not lower than 10 10 /cm 2, with the use of a solution containing: 0,25% of nanodiamond with average grain size 10 nm, 0,5% of polyvinyl alcohol and dimethyl sulfoxide as a solvent; c) Application of an adhesive diamond layer in the CVD (Chemical Vapor Deposition) process, wherein the nucleated electrode substrate from step b) is heated up to 500 °C under conditions that a hydrogen rich microwave plasma contains 4% by volume of methane and 5000 ppm by volume of boron supplied as diborane precursor (B 2 H 6), wherein the pressure of 6,7 kPa (50 torr) and the constant flow of hydrogen of 3,34 x 10 -6 m 3 /s (200 sccm) are maintained and the process is carried out for 30 minutes with the use of microwaves at a frequency of 2,45 GHz and with a power of 1300 W; d) Application of a working electrode layer in the CVD (Chemical Vapor Deposition) process, wherein the electrode substrate from step c) is heated up to 700°C under conditions that the hydrogen rich microwave plasma contains 1% by volume of methane and 5000 ppm by volume of boron supplied as diborane precursor (B 2 H 6), wherein the pressure of 6,7 kPa (50 torr) and the constant flow of gas of 5,1 x 10 -6 m 3 /s (300 sccm) are maintained and the process is carried out for 6 hours with the use of microwaves at a frequency of 2,45 GHZ and with the power of 1300 W; e) Hydrogenation of the working layer by heating the electrode obtained from step d) to 700 °C with the presence of a hydrogen rich microwave plasma, the pressure is 5,3 kPa (40 torr) and the constant flow of hydrogen is 5,1 x 10 -6 m 3 /s (300 sccm), wherein the process is carried out for 10 minutes with the use of microwaves at a frequency of 2,45 GHz and with the power of 1300 W.