ELECTROCHEMICAL ACTIVITY OF LITHIUM NICKEL OXIDE THIN-FILM CATHODES OBTAINED BY ALD

Energy density is one of the essential characteristics of thin-film power sources which provides the duration of the autonomous performance of sensors, energy harvesters, loT devices, etc. The Atomic layer deposition (ALD) allows the growth of conformal coatings with a controlled composition on high aspect ratio substrates and can be used to manufacture some components of thin-film batteries. Modern high energy active cathode materials include Li, transition metal, and oxygen. The production of such films by the ALD method can be carried out using a linear combination of lithium oxide structures and transition metal oxide structures (supercycle approach), followed by annealing. The control of the composition and properties of the films can be achieved by varying the ratio of cycles conducted for deposition of binary oxides during supercycle. In present work, were used 1/10 and 1/30 ratio of lithium oxide/nickel oxide ALD cycles during supercycle to obtain thin films of Li-Ni-O system. X-ray photoelectron spectroscopy of the as-deposited films demonstrates low nickel content in films. The annealed films at 800 and 900 degrees C for 10 minutes show the presence of the lithium silicates and nickel silicide phases. It was found that the best electrochemical performance show samples of LNO 1/30 series annealed at 800 degrees C: at a discharge current of 20 mu A (5C), the capacity was equal to 35 mu A.h.mu m(-1).cm(-2). The obtained results demonstrate a low effect of an increase in the number of cycles on the proportion of nickel in the films and, consequently, on the electrochemical characteristics.