Remote Plasma Atomic Layer Deposition of Thin Films of Electrochemically Active LiCoO₂

Abstract

One of the remaining challenges in the field of portable electronics is the miniaturization of lithium-ion batteries without decreasing their storage capacity. To tackle this challenge and to effectively integrate battery technology in even a wider variety of applications, it is essential to produce high quality thin films for all-solid-state batteries. A remote plasma ALD process for the positive electrode material LiCoO2 was developed using the combination of CoCp2 as the cobalt precursor, LiOtBu as the lithium precursor and O2 plasma as the oxidant source. The thin films were deposited at a temperature of 325 °C with a virtually linear growth rate of 0.06 nm/cycle. After annealing the samples at 700 °C for 6 minutes the high temperature phase LiCoO2 was obtained, as demonstrated by XRD and Raman spectroscopy measurements. Electrochemical charge/discharge cycling showed good electrochemical activity with a promising storage capacity.

Metal Fluorides as Lithium-Ion Battery Materials: An Atomic Layer Deposition Perspective

“…Despite this, only two reports from one group on the deposition of LiCoO 2 by ALD can be found in the literature [87,88]. It appears that the challenges in cobalt oxide deposition have had an effect on the research of the lithiated material.…”

“…The resulting films were amorphous and showed a linear increase in thickness as a function of deposited supercycles. The material could also be deposited onto carbon nanotubes (CNTs) [87] The CNT-based films were amorphous but crystallization to orthorhombic LiFePO 4 was observed after annealing in argon at 700 • C for 5 h. The Fe:P ratio in the annealed film was 0.9, as determined by EDX (energy-dispersive X-ray spectroscopy). Unfortunately, no compositional information on Li content was given.…”

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

“…Thin films of solid electrolytes, such as Li 7 La 3 Zr 2 O 12 [23], Li 7 La 2.75 Ca 0.25 Zr 1.75 Nb 0.25 O 12 [24], LiPON [25][26][27][28], LiNbO 3 [29][30][31], lithium phosphate (LPO) [15], LiTaO 3 [31][32][33][34], LiAlO x [35,36], lanthanum titanate, lithium lanthanum titanate (LLT) [37], lithium silicates [38], Li 2 O-Al 2 O 3 [39], and Li 3 BO 3 -Li 2 CO 3 [40] were also effectuated by ALD. The possibility of obtaining operable cathode materials composed of LiFePO 4 [41][42][43], LiCoO 2 [44,45], Li x Mn 2 O 4 [46], β-MnO 2 [47], MnO/LiMn 2 O 4 [48], and V 2 O 5 , Li 0.2 V 2 O 5 [49][50][51][52] was also demonstrated.…”

Atomic and molecular layer deposition in pursuing better batteries

“…In the work, V 2 O 5 nanofilms were synthesized and electrochemically tested for lithium-storage. Since that time until 2011, there had a second process for LIB cathodes in which LCO was grown via plasma-enhanced ALD (PE-ALD) [153]. Subsequently, amorphous FePO 4 [154], polycrystalline Li x Mn 2 O 4 [155], and LiFePO 4 [92] were reported.…”