Fast X‐ray Nanotomography with Sub‐10 nm Resolution as a Powerful Imaging Tool for Nanotechnology and Energy Storage Applications

Abstract

nano-computed-tomography (nano-CT). They have emerged in many synchrotrons worldwide [1][2][3][4][5][6] and have been widely used in energy science where typical spatial resolutions of 30-60 nm and respective field of view (FOV) of about 40-70 μm are ideal for the ex situ or in situ characterization of different type of lithium-ion batteries. [7][8][9][10][11][12] However, they can be also utilized to characterize any type of materials like alloys, [13,14] rocks, [15] single minerals in solution, [16,17] polymers, [18] liquids, [19] biological tissues, [20] etc. While 19 nm spatial resolution has been reported in 2D on gold test patterns with long exposure, [21,22] existing TXMs operating with high brightness synchrotron sources currently provide a maximum resolution of 30 nm. [23] Projection microscopy, another full-field nano-CT technique, has the potential of achieving sub-20 nm spatial resolution. However, the best 3D resolution reported so far is 55 nm. [24] The constant and rapid development of manufactured nanomaterials and the societal and economic stakes associated with them are important drivers for improving the resolving power of X-ray microscopes.In the last decade, transmission X-ray microscopes (TXMs) have come into operation in most of the synchrotrons worldwide. They have proven to be outstanding tools for non-invasive ex and in situ 3D characterization of materials at the nanoscale across varying range of scientific applications. However, their spatial resolution has not improved in many years, while newly developed functional materials and microdevices with enhanced performances exhibit nanostructures always finer. Here, optomechanical breakthroughs leading to fast 3D tomographic acquisitions (85 min) with sub-10 nm spatial resolution, narrowing the gap between X-ray and electron microscopy, are reported. These new achievements are first validated with 3D characterizations of nanolithography objects corresponding to ultrahigh-aspect-ratio hard X-ray zone plates. Then, this powerful technique is used to investigate the morphology and conformality of nanometer-thick film electrodes synthesized by atomic layer deposition and magnetron sputtering deposition methods on 3D silicon scaffolds for electrochemical energy storage applications.

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

“…One can note that the other deposition techniques could not be used for 3D Li-ion microbatteries owing to their nonconformal issue. [39] The surface capacity of the 100 nm thick LMO film reported here (this work 1) is close to 180 µAh cm −2 when measured at C/20. The performance at other C-rates was already discussed previously (Figure 5).…”

“…Indeed, 7.4 µm thick sputtered LiNi 0.5 Mn 1.5 O 4 film made by our group recently [ 31 ] for planar Li‐ion microbatteries was able to deliver ≈400 µAh cm −2 but it is well know that magnetron sputtering technique could not be used to coat 3D template due to nonconformal issue. [ 39 ] More specifically, we also show that sputtered thick LiNi 0.5 Mn 1.5 O 4 film suffer from mechanical issue due to the stress occurring within the 7.4 µm thick electrode. [ 31 ] The capacity of “this work 1” sample is at the same level of magnitude than the capacity reported by Navone et al.…”

“…One can note that the other deposition techniques could not be used for 3D Li‐ion microbatteries owing to their nonconformal issue. [ 39 ]…”

“…The sector is equipped with the transmission X‐ray microscope (TXM) demonstrating up to 10 nm resolution levels in 3D volume reconstructions. [ 39 ] Nano‐CT measurements were performed for two samples: Si microtube with Al 2 O 3 (90 nm)/Pt (30 nm)/LiMn 2 O 4 (150 nm), and Si microtube with Al 2 O 3 (90 nm)/Pt (20 nm)/LiMn 2 O 4 (180 nm)/Li 3 PO 4 (85 nm). X‐ray projections were acquired in absorption mode at 8 keV in the interlaced scanning mode with 1.6 s exposure and 0.4 s sample stabilization time per projection.…”

Improving a Rapid Alignment Method of Tomography Projections by a Parallel Approach

“…Without proper correction, a dataset acquired under these circumstances is completely unusable, as a severe point spread function [14] is introduced in the reconstruction, jointly with a peculiar artefact [13]. Even if in some cases the error component can be measured and corrected [15] (also with interferometric encoding of the specimen position [11]), this is not the case of special setups, such as the one employing cryo-stages [12,16], for which even more advanced opto-mechanical outbreaks than the ones described in [17] are required to reach a sub-10 nm resolution. Post-acquisition alignment is thus usually necessary [12].…”