Lithium Titanium Oxide Research Articles

Calendar ageing modelling using machine learning: an experimental investigation on lithium ion battery chemistries.

Background: The phenomenon of calendar ageing continues to have an impact on battery systems worldwide by causing them to have undesirable operation life and performance. Predicting the degradation in the capacity can identify whether this phenomenon is occurring for a cell and pave the way for placing mechanisms that can circumvent this behaviour. Methods: In this study, the machine learning algorithms, Extreme Gradient Boosting (XGBoost) and artificial neural network (ANN) have been used to predict the calendar ageing data belonging to six types of cell chemistries namely, Lithium Cobalt Oxide, Lithium Iron Phosphate, Lithium Manganese Oxide, Lithium Titanium Oxide, Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide. Results: Prediction results with overall Mean Absolute Percentage Error of 0.0126 have been obtained for XGBoost algorithm. Among these results, Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide type cell chemistries stand out with their mean absolute percentage errors of 0.0035 and 0.0057 respectively. Also, algorithm fitting performance is relatively better for these chemistries at 100% state of charge and 60°C temperature compared to ANN results. ANN algorithm predicts with mean absolute error of approximately 0.0472 overall and 0.0238 and 0.03825 for Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide. The fitting performance of ANN for Nickle Manganese Cobalt Oxide at 100% state of charge and 60°C temperature is especially poor compared to XGBoost. Conclusions: For an electric vehicle battery calendar ageing prediction application, XGBoost can establish itself as the primary choice more easily compared to ANN. The reason is XGBoost's error rates and fitting performance are more usable for such application especially for Nickel Cobalt Aluminum Oxide and Nickel Manganese Cobalt Oxide chemistries, which are amongst the most demanded cell chemistries for electric vehicle battery packs.

Enhancement of optical and electrical properties of polyether sulfone by addition of Li4Ti5O12 NPs

Nanocomposite films were made from polyether sulfone (PES) and lithium titanium oxide nanoparticles (Li4Ti5O12 NPs). In this work, the effect of addition of Li4Ti5O12 NPs on the PES on the optical and electrical performance was investigated. Different techniques were used to study the characteristics the physicochemical properties of the prepared polymer nanocomposites samples. XRD and FT-IR affirmed the interaction between PES and Li4Ti5O12 NPs. The degree of crystallinity from XRD revealed that the addition of Li4Ti5O12 NPs increases the crystallinity of PES. The formation of charge transfer complexes between PES and Li4Ti5O12 NPs was revealed by UV/Vis analysis. Based on the dielectric measurements, Li4Ti5O12 NPs are a promising candidate for use as dopants in PES polymer in order to improve the material's electrical properties. In addition to, the produced results showed that the prepared samples can be promising in broad potential applications as Li-ion batteries, electrochemical and industrial applications, and optoelectronic devices.

Dual additive of lithium titanate and sulfurized pyrolyzed polyacrylonitrile in sulfur cathode for high rate performance in lithium-sulfur battery.

Lithium-Sulfur (Li-S) batteries have attracted much attention as next-generation batteries due to their high theoretical energy density. However, lithium polysulfide generated during the discharge loses intimate electrical contact with the carbon matrix due to its high solubility in the electrolyte, causing a high charge transfer resistance and slow redox kinetics for the discharge reactions, resulting in a low rate capability. A cathode additive having a strong chemical adsorbing site toward the polysulfide can effectively inhibit their dissolution. We now report a dual additive of lithium titanium oxide (LTO) and sulfurized polyacrylonitrile (SPAN). LTO provides a rapid charge transfer and a fast Li+ ion transfer in the cathode. On the other hand, SPAN helps to enhance the polysulfide adsorption capability. This dual additive system synergistically supplies the cathode with a strong polysulfide adsorption capability and fast redox kinetics. As a result, the dual additive exhibits high discharge capacities of 1430 mA h g-1 at 0.1C and 1200 mA h g-1 at 0.5C at the high-sulfur-loading cathode of 5.0 mg cm-2. Our findings demonstrated the manufacturing of the cathode with a strong polysulfide adsorption capability and a fast redox reaction which could then effectively improve the rate performance of the Li-S batteries.

Micrometer-scale single crystalline particles of niobium titanium oxide enabling an Ah-level pouch cell with superior fast-charging capability.

Wadsley-Roth phase niobium titanium oxide (TiNb2O7) is widely regarded as a promising anode candidate for fast-charging lithium-ion batteries due to its safe working potential and doubled capacity in comparison to the commercial fast-charging anode material (lithium titanium oxide, Li4Ti5O12). Although good fast charge/discharge performance was shown for nanostructured TiNb2O7, the small size would cause the low electrode compensation density and energy density of batteries, as well as parasitic reactions. Fundamental understanding of the electrochemical lithium insertion/extraction process and the structural evolution for the micrometer-scale single crystalline TiNb2O7 (MSC-TiNb2O7) could provide insights to understand its inherent properties and possibility for fast-charging application. Here, we revealed the highly reversible structural evolution of the MSC-TiNb2O7 during the lithiation/delithiation processes. Interestingly, an ion-conductive lithium niobate interphase was in situ formed on the MSC-TiNb2O7 surface during the formation cycle, which could facilitate fast ion diffusion on the material surface and support fast electrochemical reaction kinetics. Experimentally, the MSC-TiNb2O7 delivered a high reversible capacity of 291.9 mA h g-1 at 0.5C with a high initial Coulombic efficiency (>95%), and showed superb rate capability with a reasonable capacity of 55.6 mA h g-1 under a high current density of 40C. An Ah-level pouch cell with a lithium cobalt oxide (LiCoO2) cathode exhibited 91.5% capacity retention at 3C charging rate, which revealed the significant role of high crystallinity and in situ formation of an ion conductive nano-interphase in realizing fast charging capability of practical TiNb2O7-based lithium-ion batteries.

Application and limitations of batteries and hydrogen in heavy haul rail using Australian case studies

Decarbonisation of heavy haul rail is an essential contributor to a zero-emissions future. However, the transition from diesel to battery locomotives is not always practical, given the unique characteristics of each haul. This paper demonstrates the limitations of state-of-the-art batteries using real-world data from multiple locomotives operating in Australian rail freight. An energy model was developed to assess each route's required energy and potential regenerated energy. The tractive and regenerative battery energy, mass, and cost were determined using data from the energy model coupled with battery specifications. The feasibility of implementing lithium iron phosphate (LFP), nickel manganese cobalt (NMC) and lithium titanium oxide (LTO) chemistries was explored based on cost, energy density, cycle lifespan and locomotive data. LFP was identified as the most suitable current battery solution based on current chemistries. Further examination of the energy demands, and associated mass/volume constraints concluded that three platforms are required for heavy haul rail decarbonisation i) a battery electric locomotive for low-energy demands, which can be coupled with either ii) a battery electric tender for medium energy demands or iii) a hydrogen fuel cell electric tender for higher energy demands. A future-looking techno-economic assessment of battery and hydrogen fuel cell platforms concludes that the lowest cost solution for low-energy hauls is a battery-only system, and for high-energy hauls, a battery-hydrogen system.

Green aqueous binder poly(N-vinylformamide) for high-rate capability Li4Ti5O12 anode in lithium-ion batteries

To persue sustainable developments, poly (N-vinylformamide) (PNVF) is investigated as a green, bio-derived and water-soluble binder for Li4Ti5O12 (LTO) anode in lithium-ion batteries (LIBs). Electrochemical performance differences between PNVF electrodes and the conventional polyvinylidene fluoride (PVDF) electrodes are presented. The electrodes are characterized by peeling test, the galvanostatic charge/discharge cycle test, electrochemical impedance analysis (EIS), cyclic voltammetry (CV) and scanning electron microscope (SEM). The electrode with 3 wt% PNVF shows higher peeling force than the one with 10 wt% PVDF. The electrodes with 3 wt% PNVF and 10 wt% PVDF exhibit similar rate capability, whereas the capacity retention at 1C-rate is 91.2% (144 mAh/g) and 76.1% (123 mAh/g) after 1000 cycles, respectively. EIS and CV results exhibit that the lithium-titanium oxide (LTO) electrode with optimal PNVF binder (3 wt%) shows lower RSEI and Rct values as compared to that with PVDF counterpart and optimal PNVF electrode exhibits high lithium-ion diffusion coefficient. To enhance the cyclability and high-rate performance, vinylene carbonate (VC) is added as an electrolyte additive afterwards, and the results improve accordingly. Therefore, the results present in this paper demonstrated that PNVF is a potential aqueous binder for LTO anode within green fabrication.

Correlation between Lithium Titanium Oxide Powder Morphology and High Rate Performance in Lithium-Ion Batteries

This study determined the measurable factor responsible for the high rate performance of lithium titanium oxide (Li4Ti5O12, LTO) powders in lithium-ion batteries. The structural and morphological properties of various Li4Ti5O12 materials and their correlation with electrochemical performance were analysed. The results showed that there was a strong correlation between high capacity retention at 10 C and the specific surface area. Other electrochemical and structural factors, such as the crystal size and pore structure, were not correlated with 10 C performance. We found that an increase in the specific surface area of Li4Ti5O12 above c.a. 15 m2 g−1 neither improved the high rate capacity retention nor its specific discharge capacity at high current rates. We also showed that the sol–gel synthesized lithium titanium oxide powders could retain similar or higher discharge specific capacities than materials synthesized via more complex routes.

Extraction of lithium in salt lake brine through highly selective titanium ion sieves - A review

With the large-scale application and development of lithium-ion batteries, the extraction of lithium resources from salt lake brine has gradually become a global focus. Lithium titanium oxides (LTO)-type lithium ion-sieve (LIS) has attracted much attention due to its stable structure, high adsorption capacity, excellent recycling capacity, and environmental protection. In this review, we focused on the structure and adsorption mechanism of titanium-based ion sieves, and the preparation methods of different titanium oxide precursors. Furthermore, three modification methods including ion doping, morphology control, and surface coating were summarized. Finally, the insufficiency problem of current research is proposed, and the improvement and application of titanium-based LIS are prospected.

Calendar ageing modelling using machine learning: an experimental investigation on lithium ion battery chemistries

Background: The phenomenon of calendar ageing continues to have an impact on battery systems worldwide by causing them to have undesirable operation life and performance. Predicting the degradation in the capacity can identify whether this phenomenon is occurring for a cell and pave the way for placing mechanisms that can circumvent this behaviour. Methods: In this study, the machine learning algorithms, Extreme Gradient Boosting (XGBoost) and artificial neural network (ANN) have been used to predict the calendar ageing data belonging to six types of cell chemistries namely, Lithium Cobalt Oxide, Lithium Iron Phosphate, Lithium Manganese Oxide, Lithium Titanium Oxide, Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide. Results: Prediction results with overall Mean Absolute Percentage Error of 0.0126 have been obtained for XGBoost algorithm. Among these results, Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide type cell chemistries stand out with their mean absolute percentage errors of 0.0035 and 0.0057 respectively. Also, algorithm fitting performance is relatively better for these chemistries at 100% state of charge and 60°C temperature compared to ANN results. ANN algorithm predicts with mean absolute error of approximately 0.0472 overall and 0.0238 and 0.03825 for Nickle Cobalt Aluminum Oxide and Nickle Manganese Cobalt Oxide. The fitting performance of ANN for Nickle Manganese Cobalt Oxide at 100% state of charge and 60°C temperature is especially poor compared to XGBoost. Conclusions: For an electric vehicle battery calendar ageing prediction application, XGBoost can establish itself as the primary choice more easily compared to ANN. The reason is XGBoost’s error rates and fitting performance are more usable for such application especially for Nickel Cobalt Aluminum Oxide and Nickel Manganese Cobalt Oxide chemistries, which are amongst the most demanded cell chemistries for electric vehicle battery packs.

How the Sodium Cations in Anode Affect the Performance of a Lithium-ion Battery

Large cations such as potassium ion (K+) and sodium ion (Na+) could be introduced into the lithium-ion (Li-ion) battery system during material synthesis or battery assembly. However, the effect of these cations on charge storage or electrochemical performance has not been fully understood. In this study, sodium ion was taken as an example and introduced into the lithium titanium oxide (LTO) anode through the carboxymethyl cellulose (CMC) binder. After the charge/discharge cycles, these ions doped into the LTO lattice and improved both the lithium-ion diffusivity and the electronic conductivity of the anode. The sodium ion’s high concentration (>12.9%), however, resulted in internal doping of Na+ into the LTO lattice, which retarded the transfer of lithium ions due to repulsion and physical blocking. The systematic study presented here shows that large cations with an appropriate concentration in the electrode would be beneficial to the electrochemical performance of the Li-ion battery.

Synthesis of Lithium Titanium Oxide (Li<sub>4</sub>Ti<i><sub>5</sub></i>O<sub>12</sub>) through Sol-Gel Method and the Effect of Graphene Addition in Lithium-Ion Battery Anodes

Li4Ti5O12 (lithium titanium oxide) or LTO is extensively utilized as active material in Li-ion battery anode mainly due to its zero strain properties and excellent lithium-ion intercalation/deintercalation reversibility with negligible volumetric change. However, LTO is still faced with low electronic conductivity problem, thus the addition of another material such as graphene is necessary to overcome. In this study, LTO was synthesized using sol-gel method with addition of Li varied from 35, 40 and 55 wt% which was controlled by addition of Li2CO3. XRD analysis was performed to investigate the crystal structure and phase characteristic of synthesized powder. The results revealed that LTO with addition of 55 wt% Li exhibited the highest purity of Li4Ti5O12 phase of 97.7%. It was then added with 5 wt% of graphene. Two-coin cells of Li-ion batteries were made from LTO powders without and with graphene addition as active materials for anode and their electrochemical performances were analyzed. LTO without and with graphene show conductivity of 3.40710-5 and 2.48810-5 S/cm, while obtained specific capacity was about 140 mAH and 85 mAh, respectively. This would require further optimization for current experimental condition particularly on graphene addition.

Deciphering the Interplay between Binders and Electrolytes on the Performance of Li4Ti5O12 Electrodes for Li-Ion Batteries

Lithium titanium oxide (Li4Ti5O12, LTO) is an attractive negative electrode for the development of safe—next-generation—lithium-ion batteries (LIBs). LTO can find specific applications complementary to existing alternatives for LIBs thanks to its good rate capability at high C-rates, fast lithium intercalation, and high cycling stability. Furthermore, LIBs featuring LTO electrodes are inherently safer owing to the LTO’s operating potential of 1.55 V vs. Li+/Li where the commonly used organic-based electrolytes are thermodynamically stable. Herein, we report the combined use of water-soluble sodium alginate (SA) binder and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-tetraglyme (1m-T) electrolyte and we demonstrate the improvement of the electrochemical performance of LTO-based electrodes with respect to those operating in conventional electrolyte 1M LiPF6-ethylene carbonate: dimethyl carbonate (LP30). We also tackle the analysis of the impact of combining the binder/electrolyte on the long-term cycling performance of LTO electrodes featuring SA or conventional polyvinylidene fluoride (PVdF) as binders. Therefore, to assess the impact of the combination of binder/electrolyte on performance, we performed post-mortem characterization by ex situ synchrotron diffraction experiments of LTO electrodes after cycling in LP30 and 1m-T electrolytes.

Application of Poly-L-Lysine for Tailoring Graphene Oxide Mediated Contact Formation between Lithium Titanium Oxide LTO Surfaces for Batteries.

When producing stable electrodes, polymeric binders are highly functional materials that are effective in dispersing lithium-based oxides such as Li4Ti5O12 (LTO) and carbon-based materials and establishing the conductivity of the multiphase composites. Nowadays, binders such as polyvinylidene fluoride (PVDF) are used, requiring dedicated recycling strategies due to their low biodegradability and use of toxic solvents to dissolve it. Better structuring of the carbon layers and a low amount of binder could reduce the number of inactive materials in the electrode. In this study, we use computational and experimental methods to explore the use of the poly amino acid poly-L-lysine (PLL) as a novel biodegradable binder that is placed directly between nanostructured LTO and reduced graphene oxide. Density functional theory (DFT) calculations allowed us to determine that the (111) surface is the most stable LTO surface exposed to lysine. We performed Kubo–Greenwood electrical conductivity (KGEC) calculations to determine the electrical conductivity values for the hybrid LTO–lysine–rGO system. We found that the presence of the lysine-based binder at the interface increased the conductivity of the interface by four-fold relative to LTO–rGO in a lysine monolayer configuration, while two-stack lysine molecules resulted in 0.3-fold (in the plane orientation) and 0.26-fold (out of plane orientation) increases. These outcomes suggest that monolayers of lysine would specifically favor the conductivity. Experimentally, the assembly of graphene oxide on poly-L-lysine-TiO2 with sputter-deposited titania as a smooth and hydrophilic model substrate was investigated using a layer-by-layer (LBL) approach to realize the required composite morphology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM) were used to characterize the formed layers. Our experimental results show that thin layers of rGO were assembled on the TiO2 using PLL. Furthermore, the PLL adsorbates decrease the work function difference between the rGO- and the non-rGO-coated surface and increased the specific discharge capacity of the LTO–rGO composite material. Further experimental studies are necessary to determine the influence of the PLL for aspects such as the solid electrolyte interface, dendrite formation, and crack formation.

Influence of external pressure on silicon electrodes in lithium-ion cells

The influence of external pressure on lithium-ion cells containing a silicon anode is investigated. The performance of pouch-type full cells under rigid compression is compared to unconstrained cells, where the electrode stack is allowed to swell during cycling. The negative electrode contains only silicon as active material, while prelithiated lithium titanium oxide (LTO) is used as the positive electrode. The results show that the main failure mechanism in such cells is a continuous irreversible consumption of lithium ions, likely due to repeated solid electrolyte interphase breakage and reformation. At high pressures, the lithium depletion has a larger influence than at lower pressures. This effect is examined by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) as well as dilation measurements of flexibly-constrained cells and can be traced back to an increase of the ionic pore resistance being more pronounced under high pressure. A new approach is used to compensate the lithium loss, i.e. internal relithiation of the LTO electrode via a lithium reservoir. This not only proves the theory of irreversible lithium consumption being the main challenge in these cells, but also enables cycling for 1000 cycles at 1200 mAhgSi−1 without capacity fading.

A High Energy Density Li-ion Battery with Lithium Titanium Oxide Anode

A High Energy Density Li-ion Battery with Lithium Titanium Oxide Anode

Role of gelatin and chitosan cross-linked aqueous template in controlling the size of lithium titanium oxide

Significant safety advantages of lithium titanium oxide (LTO) over currently used graphite for lithium-ion batteries have been attracting scientists to develop novel synthetic methods of this anode material in order to combine with another cathode. This study utilizes self-sacrificing cross-linked aqueous templates of gelatin and chitosan polymer to control lithium titanium oxide (LTO) morphology and microstructure. Gelatin and chitosan self-assembled aqueous template containing LTO precursors has been evaporated at 110 °C and then calcined at 750 °C in a muffle furnace to synthesize white color LTO powder. Various techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Energy dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and UV–visible spectroscopy were used to characterize the synthesized LTO powders. Both XRD and EDS spectrum confirm the coating of gelatin and chitosan derived carbon species on the surface of LTO materials. The detailed characterization reveals that increasing the amount of gelatin to the mass ratio of gelatin and chitosan reduced LTO particle sizes. Thus, a size controlled carbon coating LTO preparation strategy have been established via gelatin and chitosan cross-linked aqueous template in controlling the morphology and microstructure of LTO material.

Stable and Reversible Lithium Storage Properties of LiTiOx Nanotubes for Electrochemical Recovery from Aqueous Solutions

AbstractIn the present work, an easy and scalable method to prepare lithium titanium oxide nanotubes with stable and reversible lithium storage properties is reported. This material could be an excellent candidate for lithium recovery from aqueous solutions or have a direct application as Li‐ion batteries electrodes in a circular economy perspective. Vertically oriented anatase nanotubes are grown by anodic oxidation in an ethylene glycol‐based electrolyte. Then, the nanotubes are hydrothermally converted into a mixed lithium titanate. Morphological and crystallographic characterizations confirm the successful shape‐preserving conversion after which the nanotubes are subjected to electrochemical cycling. XRD and XPS analyses confirm a significant lithium uptake after cycling, and its recovery is investigated by means of an acidic treatment. While allowing for an almost complete recovery of the lithium integrated in their structure, the nanotubes also showed excellent morphological and structural stability proving to be excellent candidates for lithium recovery purposes.

Safe extended-range cycling of Li4Ti5O12-based anodes for ultra-high capacity thin-film batteries

Lithium titanium oxide thin films are increasingly popular anode materials in microbatteries and hybrid supercapacitors, due to their improved safety, cost, and cycle lifetime. So far, research efforts have mainly focused on the pure spinel phase Li4Ti5O12 (LTO) and only a small fraction is dedicated to a broader spectrum of titanium-based metal oxide thin films. In this work, pulsed laser deposition is used in a multilayer approach by alternating LTO and Li2O ablations to create a heterogeneous landscape in the titania-based micro-anodes. This rich microstructure enables the safe extension of the accessible electrochemical window down to 0.2 V. This leads to extraordinary high specific capacities of 250–300 mAh/g at 1 C, maintaining a stable discharge capacity of 180 mAh/g at 16 C. Operando spectroscopic ellipsometry and Raman spectroscopy are used to track optical and structural changes as a function of the discharge voltage down to 0.01 V. A kinetically limited degradation mechanism based on the effective trapping of Li-ions at the octahedral 16c positions is proposed when cycling in the range of 0.2–0.01 V. In essence, our work contributes to titania-based nanoshapes as anodes of increased specific capacity due to a higher Li-site occupation, while maintaining their good stability and safety.

Examining the Performance of Implantable-Grade Lithium-Ion Cells after Overdischarge and Thermally Accelerated Aging

For implanted medical devices containing rechargeable batteries, maximizing battery lifetime is paramount as surgery is required for battery replacement. In non-life-sustaining applications (e.g., spinal cord stimulators or sacral nerve modulation), these implants may be left unused and unmaintained for extended periods, according to patient preference or in the case of unexpected life events. In this study, we examine the performance of two commercial lithium-ion cells intended for implantable neurostimulators (using lithium titanium oxide (LTO) and graphite as the negative electrode) when subjected to repeated deep overdischarge and to aging at a high state of charge (SOC). The graphite-based cells exhibited significant performance decline and swelling after overdischarge and became unable to store a charge after 42 days at 0 V. In contrast, the LTO-based cells exhibited minimal changes in performance even after 84 days (the length of the study) at 0 V. When subjected to an accelerated aging protocol at 100% SOC, the graphite-based cells were found to age more rapidly than the LTO cells, which exhibited minimal aging over the course of the study period. These results show that practical LTO-based lithium-ion cells are much more tolerant of abuse as a result of neglect and misuse and are worth considering for use in high-value applications where battery replacement is difficult or impossible.

Unveiling scale differences in the two-phase transformation of [formula omitted][formula omitted][formula omitted] via operando X-ray absorption and diffraction studies

Lithium titanium oxide Li4Ti5O12 (Li[Li1/3Ti5/3]O4) has been receiving significant attention as an ideal electrode material for lithium-ion batteries, because its cubic lattice parameter (ac) changes negligibly during the electrochemical reaction. However, this same characteristic hinders in-depth understanding of the reaction mechanism, restricting widespread applications, such as use in electric vehicles. We thus employed the recently developed operando X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) technique, combined with multivariate curve resolution by alternating least squares (MCR-ALS) method. The MCR-ALS analyses of both the XAS and XRD data confirmed a two-phase reaction scheme consisting of Li[Li1/3Ti5/3]O4 and Li2[Li1/3Ti5/3]O4, but differences in the structural transformations clearly appeared at the two different scales. Linear, reversible changes in the bond distance between Ti and O atoms were observed at the atomic scale (∼1 nm), whereas hysteresis in ac between the discharge and charge reactions was observed at the microscale (∼100 nm). This difference was found to originate from the difference in spatial resolutions between the XAS and XRD techniques.