3D LiMn₂O₄ Thin Film Deposited by ALD: A Road toward High‐Capacity Electrode for 3D Li‐Ion Microbatteries

Abstract

Miniaturized electronics suffer from a lack of energy autonomy. In that context, the fabrication of lithium‐ion solid‐state microbatteries with high performance is mandatory for powering the next generation of portable electronic devices. Here, the fabrication of a thin film positive electrode for 3D Li‐ion microbatteries made by the atomic layer deposition (ALD) method and in situ lithiation step is demonstrated. The 3D electrodes based on spinel LiMn2O4 films operate at high working potential (4.1 V vs Li/Li+) and are capable of delivering a remarkable surface capacity (≈180 μAh cm−2) at low C‐rate while maintaining more than 40 μAh cm−2 at C/2 (time constant = 2 h). Both the thickness of the electrode material and the 3D gain of the template are carefully tuned to maximize the electrode performance. Advanced characterization techniques such as transmission electron and X‐ray transmission microscopies are proposed as perfect tools to study the conformality of the deposited films and the interfaces between each layer: no interdiffusion or segregation are observed. This work represents a major issue towards the fabrication of 3D‐lithiated electrode by ALD—without any prelithiation step by electrochemical technique—making it an attractive solution for the fabrication of 3D Li‐ion solid‐state microbatteries with semiconductor processing methods.

Toward Optimization of the Chemical/Electrochemical Compatibility of Halide Solid Electrolytes in All-Solid-State Batteries

“…This was made possible here through an interfacial engineering process using a nanometer-thick Li 3 PO 4 surface protective layer (∼1 or 2 nm) deposited by ALD technique on a single surface of a Li 6 PS 5 Cl separator pellet, delivering a similarly high ionic conductivity (Figure S12). This Li 3 PO 4 surface protective layer made by ALD was proposed recently to stabilize the interface of sputtered LiNi 0.5 Mn 1.5 O 4 or LiMn 2 O 4 (made also by ALD) films for planar or 3D Li-ion microbattery applications. , The high conformity (i.e., the ability to coat a complex surface with a homogeneous layer showing no variation of the film thickness) and pinhole-free behavior of Li 3 PO 4 films naturally recommended the ALD method as a suitable candidate for mastering the interface in ASSBs. It is noteworthy that STEM-EDX and STEM-EELS mapping revealed the Li 3 PO 4 coating, but determination of its distribution and thickness was practically challenging, owing to the rough surface of the Li 6 PS 5 Cl substrate pellets (Figures S13–S15).…”

A hybrid machine-learning approach for analysis of methane hydrate formation dynamics in porous media with synchrotron CT imaging

“…This can be observed, for instance, in materials science and geology: low-contrast phases observed in CT imaging of carbonate samples (Alqahtani et al, 2022) and carbon/epoxy woven composites (Sinchuk et al, 2020). Other examples include nano-CT in battery research (Hallot et al, 2022) or chemical science (Kim et al, 2023). Fast segmentation procedures can aid in localizing regions of interest and selecting time intervals for studying dynamic phenomena, as well as providing quantitative estimations of sample components for input into digital rock physics simulations (Wang et al, 2015;Sell et al, 2016).…”

Three-Dimensional TiO2 Film Deposited by ALD on Porous Metallic Scaffold for 3D Li-Ion Micro-Batteries: A Road towards Ultra-High Capacity Electrode

“…To tackle this issue, Atomic Layer Deposition technique remains the best deposition method to produce 3D Li-ion solid-state micro-batteries on large-scale wafers. Current collectors 4,5 (Pt, TiN), positive electrode [6][7][8][9][10] (LiCoO 2 , LiFePO 4 , LiMn 2 O 4 …), solid electrolyte [11][12][13][14][15] (Li 3 PO 4 , LIPON, Li 7 La 3 Zr 2 O 12 …) and negative electrodes 11,[16][17][18][19][20] (TiO 2 , V 2 O 5 , Nb 2 O 5 , Li 4 Ti 5 O 12 …) have already been investigated as efficient thin films for all solid-state 3D Li-ion micro-battery. Among the existing functional electrodes made from ALD facility, bulk or nanostructured titanium dioxide is a promising alternative material to graphite and silicon based negative electrodes in a Li-ion battery owing to the low toxicity, low cost and safety issue.…”

“…This is the highest capacity value reported up to now with such low amount of active material. When combined with a suitable positive electrode material6,10 (LiMn 2 O 4 , LiCoO 2 ), such 3D TiO 2-based negative electrode could deliver high energy density values, opening the way to high performance Li-ion microbatteries for efficiently powering miniaturized electronics devices. TiO 2 films were deposited by ALD on a planar substrate composed of stacked Al 2 O 3 / Pt layers on a silicon wafer as already reported by our group in previous publications11,31,41,42 .…”