Atomic Layer Deposition of Lithium–Nickel–Silicon Oxide Cathode Material for Thin-Film Lithium-Ion Batteries

Maxim Maximov,Oleg Medvedev,Anatoly Popovich,Ilya Mitrofanov,Artem Kim,Ilya Ezhov,Denis Nazarov,Aleksander Rumyantsev,Yury Koshtyal

doi:10.3390/en13092345

Abstract

Lithium nickelate (LiNiO2) and materials based on it are attractive positive electrode materials for lithium-ion batteries, owing to their large capacity. In this paper, the results of atomic layer deposition (ALD) of lithium–nickel–silicon oxide thin films using lithium hexamethyldisilazide (LiHMDS) and bis(cyclopentadienyl) nickel (II) (NiCp2) as precursors and remote oxygen plasma as a counter-reagent are reported. Two approaches were studied: ALD using supercycles and ALD of the multilayered structure of lithium oxide, lithium nickel oxide, and nickel oxides followed by annealing. The prepared films were studied by scanning electron microscopy, spectral ellipsometry, X-ray diffraction, X-ray reflectivity, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and selected-area electron diffraction. The pulse ratio of LiHMDS/Ni(Cp)2 precursors in one supercycle ranged from 1/1 to 1/10. Silicon was observed in the deposited films, and after annealing, crystalline Li2SiO3 and Li2Si2O5 were formed at 800 °C. Annealing of the multilayered sample caused the partial formation of LiNiO2. The obtained cathode materials possessed electrochemical activity comparable with the results for other thin-film cathodes.

Highlights

The improvement of small, low-power devices can be achieved by the development of power sources to provide autonomous operation
We proposed distributions of Ni and O in the crystal volume correspond with the X-ray photoelectron spectroscopy (XPS) and SIMS depth profiling of stainless steel described elsewhere [72]
x-ray diffraction (XRD) data showed that the Lithium–nickel oxide (LNO)-M sample contains crystalline nickel-containing phase (NiO) and annealing at 800 ◦ C leads to the formation of Li2 Si2 O5 and probably Li5 Si22 intermetallide

Summary

Introduction

The improvement of small, low-power devices (biosensors [1], smart watches, radio-frequency identification RFID tags, Internet of Things, etc., with power requirements below 10 mW [2]) can be achieved by the development of power sources to provide autonomous operation. Lithium-ion batteries (LIBs), owing to their high energy density, cycle-life, and operational temperature range, are widely applied to power portable electronics. Considering these advantages, LIBs can be regarded as perspective power sources for the abovementioned small-sized devices. The power supply requirements are determined by device construction, functions, and operating conditions. Compact LIBs can be fabricated using traditional electrode manufacturing technology, such as a conventional casting approach [3]. Wyon produces lithium-ion cells of 6.3 mm with 160 μAh capacity and

Methods

Discussion

Conclusion