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Academic research in the battery field frequently remains limited to small coin or pouch cells, especially for new materials that are still rather far from commercialization, which renders a meaningful evaluation at an early stage of development challenging. Here, the realization of large lab-scale pouch cells comprising Sn$_{0.9}$Mn$_{0.1}$O$_{2}$ (SMO), prepared via an easily scalable hydrothermal synthesis method, as an alternative active material for the negative electrode and LiNi$_{0.6}$Mn$_{0.2}$Co$_{0.2}$O$_{2}$ (NMC$_{622}$) as a commercially available active material for the positive electrode is reported. Nine double-layer pouch cells are connected in series and parallel, suitable for powering a remote-controlled vehicle. Subsequently, these SMO‖NMC$_{622}$ cells are critically evaluated by means of an early-stage life cycle assessment and compared to graphite‖NMC$_{622}$ cells, in order to get first insights into the potential advantages and challenges of such lithium-ion chemistry.

Energy-dependent full field transmission soft X-ray microscopy (TXM) is able to give a full picture at the nanometer scale of the chemical state and spatial distribution of oxygen and other elements relevant for battery materials, providing pixel-by-pixel absorption spectrum. We show different methods to localize chemical inhomogeneities in Li1.2Mn0.56Ni0.16Co0.08O2 particles with and without VOx coating extracted from electrodes at different states of charge. Considering the 3d(Mn,Ni)-2p(O) hybridization, it has been possible to discriminate the chemical state of Mn and Ni in addition to the one of O. Different oxidation states correspond to specific features in the O-K spectra. To localize sample regions with specific compositions we apply two different methods. In the first, the pixel-by-pixel ratios of images collected at different key energies clearly highlight local inhomogeneities. In the second, introduced here for the first time, we directly correlate corresponding pixels of the two images on a xy scatter plot that we call phase map, where we can visualize the distributions as function of thickness as well as absorption artifacts. We can select groups of pixels, and then map regions with similar spectral features. Core-shell distributions of composition are clearly shown in these samples. The coating appears in part to frustrate some of the usual chemical evolution. In addition, we could directly observe several further aspects, such as: distribution of conducting carbon; inhomogeneous state of charge within the electrode; molecular oxygen profiles within a particle. The latter suggests a surface loss with respect to the bulk but an accumulation layer at intermediate depth that could be assigned to retained O2., This research was funded by Spanish Government, through the “Severo Ochoa” Programme for Centers of Excellence in R&D (FUNFUTURE CEX2019-000917-S), and the projects MAT2017-91404-EXP, RTI2018-096273-B-I00 and RTI2018-097753-B-I00 with FEDER cofunding. D.T. participates in the FLOWBAT 2021 platforms promoted by the Spanish National Research Council (CSIC). The HIU authors acknowledge the basic funding from the Helmholtz Association.

It has been shown that the introduction of several transition metal (TM) dopants into SnO2 lithium‐ion battery anodes can overcome the issues associated with the irreversible capacity loss from the conversion reaction of SnO2 and the aggregation of the metallic Sn particles formed upon lithiation. As the choice of the single dopant, however, plays a decisive role for the achievable energy density – precisely its redox potential – we investigate herein TM co‐doped SnO2, prepared by using a readily scalable continuous hydrothermal flow synthesis (CHFS) process, to tailor the dis‐/charge profile and by this the energy density. It is shown that the judicious choice of different elemental doping combinations in samples made via CHFS simultaneously improves the cycling performance and the full‐cell energy density. To support these findings, we realized a lithium‐ion full‐cell incorporating the best performing co‐doped SnO2 as negative electrode and high‐voltage LiNi0.5Mn1.5O4 (LNMO) as positive electrode–to the best of our knowledge, the first full‐cell based on such anode material in combination with LNMO as cathode active material.

ispartof: ADVANCED SUSTAINABLE SYSTEMS vol:6 issue:8 status: published

A tin-decorated reduced graphene oxide, originally developed for lithium-ion batteries, has been investigated as an anode in sodium-ion batteries. The composite has been synthetized through microwave reduction of poly acrylic acid functionalized graphene oxide and a tin oxide organic precursor. The final product morphology reveals a composite in which Sn and SnO2 nanoparticles are homogenously distributed into the reduced graphene oxide matrix. The XRD confirms the initial simultaneous presence of Sn and SnO2 particles. SnRGO electrodes, prepared using Super-P carbon as conducting additive and Pattex PL50 as aqueous binder, were investigated in a sodium metal cell. The Sn-RGO showed a high irreversible first cycle capacity: only 52% of the first cycle discharge capacity was recovered in the following charge cycle. After three cycles, a stable SEI layer was developed and the cell began to work reversibly: the practical reversible capability of the material was 170 mA&middot, h&middot, g&minus, 1. Subsequently, a material of formula NaLi0.2Ni0.25Mn0.75O was synthesized by solid-state chemistry. It was found that the cathode showed a high degree of crystallization with hexagonal P2-structure, space group P63/mmc. The material was electrochemically characterized in sodium cell: the discharge-specific capacity increased with cycling, reaching at the end of the fifth cycle a capacity of 82 mA&middot, 1. After testing as a secondary cathode in a sodium metal cell, NaLi0.2Ni0.25Mn0.75O was coupled with SnRGO anode to form a sodium-ion cell. The electrochemical characterization allowed confirmation that the battery was able to reversibly cycle sodium ions. The cell&rsquo, s power response was evaluated by discharging the SIB at different rates. At the lower discharge rate, the anode capacity approached the rated value (170 mA&middot, 1). By increasing the discharge current, the capacity decreased but the decline was not so pronounced: the anode discharged about 80% of the rated capacity at 1 C rate and more than 50% at 5 C rate.

International audience; TiO2 has been investigated as alternative anode material candidate for lithium-ion batteries for several years now due to its advantageous safety and rate capability in combination with its non-toxicity and abundance. Herein, we report the synthesis via laser pyrolysis, which allows the single-step, industrial-scale realization of carbon-coated TiO2 nanoparticles. The modification of the synthesis parameters enables the variation of the rutile-to-anatase phase ratio. Following a comprehensive physicochemical and electrochemical characterization, both the higher and lower rutile-to-anatase ratio show very stable cycling in lithium battery half-cells, while the extended presence of the rutile phase limits the achievable specific capacity and lowers the apparent lithium-ion diffusion coefficient, which leads to relatively lower capacities at elevated current densities.

The local structural and electronical transformations occurring along the first charge and discharge cycle of Li- and Mn-rich Li[Li0.2Ni0.16Mn0.56Co0.08]O2 cathode material have been characterized by X-ray absorption spectroscopy at several complementary edges. The irreversible spinel formation, occurring at the expenses of the cycling layered phase during the first charge, is quantified (about 10%) and spatially localized. The local strains induced by the Ni oxidation have been evaluated. They induce the formation of a low spin Mn3+ in the layered structure in parallel to the irreversible formation of the spinel phase in the particles bulk. The charge balance has been quantified for all the elements along the first charging cycle, confirming a reversible oxygen oxidation along the charge. Overall, these quantitative results provide an experimental basis for modeling aimed to control the structure and its evolution, for instance, hindering the spinel formation for the benefit of the material cycle life., This research was supported by the Spanish Government, through the “Severo Ochoa” Programme for Centers of Excellence in R&D (FUNFUTURE CEX2019-000917-S), and the projects MAT2017-91404-EXP, RTI2018-096273-B-I00, and RTI2018-097753-B-I00 with FEDER cofunding. D.T. participates in the FLOWBAT 2021 platforms promoted by the Spanish National Research Council (CSIC). The HIU authors acknowledge the basic funding from the Helmholtz Association.

For insertion-type lithium battery active materials, the crystal structure is of utmost importance, as it determines the possibility, reversibility, and kinetics of the Li+ de-/insertion. For alloy...

The introduction of transition metal dopants such as Fe and Co in zinc oxide enables substantially enhanced reversible capacities and greater reversibility of the de-/lithiation reactions occurring. Herein, we report a comprehensive analysis of the electrochemical processes taking place in Mn-doped ZnO (Zn0.9Mn0.1O) and carbon-coated Zn0.9Mn0.1O upon de-/lithiation. The results shed light on the impact of the dopant chemistry and, especially, its coordination in the crystal structure. When manganese does not replace zinc in the wurtzite structure, only a moderate improvement in electrochemical performance is observed. However, when applying the carbonaceous coating, a partial reduction of manganese and its reallocation in the crystal structure occur, leading to a substantial improvement in the material’s specific capacity. These results provide important insights into the impact of the lattice position of transition metal dopants—a field that has received very little, essentially no attention, so far.

High-capacity lithium-ion anodes such as alloying-, conversion-, and conversion/alloying-type materials are subjected to extensive volume variation upon lithiation/delithiation. However, a careful examination of these processes at the particle and electrode level as well as the impact of the kind of lithium-ion uptake mechanism is still missing. Herein, we investigated the volume variation upon lithiation/delithiation for a series of conversion/alloying materials with a varying relative contribution of the alloying and conversion reaction, i.e., carbon-coated ZnFe2O4, Zn0.9Fe0.1O, and Sn0.9Fe0.1O2 by operando dilatometry and ex situ scanning electron microscopy of the electrode cross section. While the theoretical estimation at the particle level indicates a rather large volume expansion of 113% (ZnFe2O4) and more, the true volume variation on the electrode level reveals very limited changes of only around 11% (ZnFe2O4). Combining the experimental findings with some theoretical considerations highlights the (to a certain extent unexpected) impact of the initial electrode porosity.

Even though electrochemically inactive, the binding agent in lithium-ion electrodes substantially contributes to the performance metrics such as the achievable capacity, rate capability, and cycling stability. Herein, we present an in-depth comparative analysis of three different aqueous binding agents, allowing for the replacement of the toxic N-methyl-2-pyrrolidone as the processing solvent, for high-energy Li1.2Ni0.16Mn0.56Co0.08O2 (Li-rich NMC or LR-NMC) as a potential next-generation cathode material. The impact of the binding agents, sodium carboxymethyl cellulose, sodium alginate, and commercial TRD202A (TRD), and the related chemical reactions occurring during the electrode coating process on the electrode morphology and cycling performance is investigated. In particular, the role of phosphoric acid in avoiding the aluminum current collector corrosion and stabilizing the LR-NMC/electrolyte interface as well as its chemical interaction with the binder is investigated, providing an explanation for the observed differences in the electrochemical performance.

Lithium-rich transition-metal-oxide cathodes are among the most promising materials for next generation lithium-ion-batteries because they operate at high voltages and deliver high capacities. However, their cycle-life remains limited, and individual roles of the transition-metals are still not fully understood. Using bulk-sensitive X-ray absorption and emission spectroscopy on Li[Li0.2Ni0.16Mn0.56Co0.08]O2, we inspect the behavior of Mn, generally considered inert upon the electrochemical process. During the first charge Mn appears to be redox-active showing a partial transformation from high-spin Mn4+ to Mn3+ in both high and low spin configurations, where the latter is expected to favor reversible cycling. The Mn redox-state with cycling continues changing in opposition to the expected charge compensation and is correlated with Ni oxidation/reduction, also spatially. The findings suggest that strain induced on the Mn−O sublattice by Ni oxidation triggers Mn reduction. These results unravel the Mn role in controlling the electrochemistry of Li-rich cathodes., This work has been partially financed by the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2015- 0496). The HIU authors kindly acknowledge the basic funding of the Helmholtz Association.

It has been shown that the introduction of several transition metal (TM) dopants into SnO2 lithium-ion battery anodes can overcome the issues associated with the irreversible capacity loss from the conversion reaction of SnO2 and the aggregation of the metallic Sn particles formed upon lithiation. As the choice of the single dopant, however, plays a decisive role for the achievable energy density – precisely its redox potential – we investigate herein TM co-doped SnO2, prepared by using a readily scalable continuous hydrothermal flow synthesis (CHFS) process, to tailor the dis-/charge profile and by this the energy density. It is shown that the judicious choice of different elemental doping combinations in samples made via CHFS simultaneously improves the cycling performance and the full-cell energy density. To support these findings, we realized a lithium-ion full-cell incorporating the best performing co-doped SnO2 as negative electrode and high-voltage LiNi0.5Mn1.5O4 (LNMO) as positive electrode–to the best of our knowledge, the first full-cell based on such anode material in combination with LNMO as cathode active material.

Choosing the right dopant: Transition metal co-doping of nanoparticulate SnO2, prepared using a readily scalable continuous hydrothermal flow synthesis process, allows for tailoring the dis-/charge profile of such material when employed as potential lithium-ion anode and, thus, enhanced full-cell energy densities and long-term cycling stability. The advantageous effect is confirmed also by realizing high-energy lithium-ion full-cells comprising the best-performing co-doped SnO2 as anode and high-voltage LiNi0.5Mn1.5O4 cathodes. It has been shown that the introduction of several transition metal (TM) dopants into SnO2 lithium-ion battery anodes can overcome the issues associated with the irreversible capacity loss from the conversion reaction of SnO2 and the aggregation of the metallic Sn particles formed upon lithiation. As the choice of the single dopant, however, plays a decisive role for the achievable energy density – precisely its redox potential – we investigate herein TM co-doped SnO2, prepared by using a readily scalable continuous hydrothermal flow synthesis (CHFS) process, to tailor the dis-/charge profile and by this the energy density. It is shown that the judicious choice of different elemental doping combinations in samples made via CHFS simultaneously improves the cycling performance and the full-cell energy density. To support these findings, we realized a lithium-ion full-cell incorporating the best performing co-doped SnO2 as negative electrode and high-voltage LiNi0.5Mn1.5O4 (LNMO) as positive electrode–to the best of our knowledge, the first full-cell based on such anode material in combination with LNMO as cathode active material., publishedVersion

This study reports the investigation of several compounds as electrolyte additives for Li[Li0.2Mn0.56 Ni0.16 Co0.08]O2 (a.k.a lithium rich NMC) cathode material. Among the compounds investigated via electrochemical and ex-situ analytical techniques, i.e. XRD, XPS and RAMAN spectroscopy, only 1,3-propane sultone and tris(trimethylsilyl) borate show a beneficial effect on the capacity retention and coulombic efficiency of the layered cathode. The results suggest that the improved capacity retention of the cells containing the two above-mentioned additives mainly originates from their participation in the formation of the cathode passive layer, which prevents the dissolution of the metals from the cathode material. Additionally, the borate additive reduces the lithium consumption upon the passive layer formation thus leaving a higher amount of lithium available in the electrolyte. Graphite/Li[Li0.2Mn0.56 Ni0.16 Co0.08]O2 cells containing the borate additive in the electrolyte showed 85% capacity retention after 485 cycles, confirming the feasibility of its employment for practical applications.

Owing to their unique combination of high energy and power density, lithium-ion batteries are now the state-of-the-art energy storage technology for powering small consumer electronics and increasingly also for large-scale applications like electric vehicles.[1] Yet, especially for the latter, there is a growing need for batteries that can provide not only high energy densities, but also the possibility to be rapidly recharged.[2] This is challenging for the currently used graphite anodes, since its low lithiation potential (~0.1 V vs. Li/Li+) in combination with the sluggish lithium transport across the solid electrolyte interphase (SEI) and within the graphite structure can lead to lithium plating and dendrite formation during fast charging, particularly at low temperatures.[3] To overcome this issue, various alternative anodes are being investigated, following, e.g., a conversion or an alloying mechanism.[4] While these alternatives frequently show higher capacities and rate capabilities, conversion materials still suffer from a significant voltage hysteresis, resulting in low energy efficiencies, and alloying materials suffer from extensive volume variations, leading to rapid capacity fading and low coulombic efficiencies. Conversion/alloying-materials (CAMs), as relatively new material class, combine the conversion and alloying mechanism in one single material.[5] In CAMs, such as Zn0.9Fe0.1O, nanograins of an alloying element and a percolating conductive network of transition metal nanoparticles are formed in situ by the initial (reversible) conversion reaction. This metallic nano-network enables fast de-/lithiation kinetics and renders them a promising candidate for high-power applications. Nevertheless, there is still a lack of knowledge about how to potentially tackle the remaining obstacles, i.e., the achievement of sufficiently high energy efficiencies and the volume variations occurring upon cycling. Herein, we report our findings towards an in-depth understanding of the de-/lithiation of (carbon-coated) Zn0.9Fe0.1O. Combining in situ microcalorimetry, in situ XRD, ex situ 7Li NMR, and ex situ 57Fe Mössbauer spectroscopy allowed us to propose a refined mechanism for the de-/lithiation reaction. Moreover, in situ dilatometry and ex situ cross-sectional SEM analysis reveal that the continuous volume variation at the electrode level is, in fact, in the range of 10%. This is much lower than theoretically predicted when considering bulk densities only – even if cycled within a 3-V potential window. Based on these results we highlight the beneficial effect of a limited operational voltage window, which we finally confirm for Zn0.9Fe0.1O/LiNi0.5Mn1.5O4 full-cells, providing an excellent energy efficiency of >93%, accompanied by an energy and power density of 284 Wh kg-1 and 1105 W kg-1, respectively. [1] N. Nitta, F. Wu, J. T. Lee, G. Yushin, Mater. Today 2015, 18, 252–264. [2] M. Li, J. Lu, Z. Chen, K. Amine, Adv. Mater. 2018, 30, 1800561. [3] J. Asenbauer, T. Eisenmann, M. Kuenzel, A. Kazzazi, Z. Chen, D. Bresser, Sustain. Energy Fuels 2020. [4] N. Loeffler, D. Bresser, S. Passerini, M. Copley, Johnson Matthey Technol. Rev. 2015, 59, 34–44. [5] D. Bresser, S. Passerini, B. Scrosati, Energy Environ. Sci. 2016, 9, 3348–3367.

Tin oxide-based materials have been intensively investigated as alternative anodes for lithium-ion batteries due to their high specific capacity, environmental friendliness, non-toxicity, and ease of handling.[1] However, the initial formation of Li2O upon lithiation is essentially irreversible, which has a severe effect on the first cycle coulombic efficiency and the reversibly achievable capacity in general.[2] It has been shown that the incorporation of transition metal dopants can address this issue, as it enables the reversible formation and reformation of Li2O.[3] The choice of the dopant, however, plays a critical role for the long-term cycling stability, rate capability, and eventual energy density of the resulting lithium-ion cells.[4] Herein, we show that the addition of specific combination of different dopants allows for further tailoring the electrochemical properties. We also demonstrate the production of such materials using a scalable continuous hydrothermal flow method. The performance of the best composition (Sn0.9Co0.05Mn0.05O2, SCMO) was further improved by applying a carbonaceous coating. The electrochemical investigation of the coated anode material was conducted in half-cells and in high-energy full-cells using high-voltage LiNi0.5Mn1.5O4 (LNMO) as active material for the cathode (Figure 1).[5] The performance of the full-cells was further enhanced by carefully optimizing the anode composition and fine-tuning the full-cell design, considering electrolytes and different pre-lithiation degrees. Reference s : [1] F. Zoller, D. Böhm, T. Bein, D. Fattakhova-Rohlfing, ChemSusChem., 1 2 , 4140 (2019) [2] I.A. Courtney and J.R. Dahn, J Electrochemical Soc., 144 , 2045 (1997) [3] D. Bresser, S. Passerini and B. Scrosati, Energy Environ. Sci. , 9 , 3348 (2016) [4] Y. Ma et al, Sustain. Energy Fuels, 2 , 2601 (2018) [5] A. Birrozzi et al., Batter. Supercaps, 3 , 284 (2020). Figure 1

The EU-funded collaborative MARS-EV Project (FP7, grant agreement 609201) has been targeting inter alia the realization of aqueous electrode processing technologies for high-energy lithium-ion positive electrodes with a particular focus on achieving the high recycling requirements established by the European Commission in its Battery Directive 2006/66 EG, stipulating a minimum recycling rate of 50%. Indeed, the aqueous electrode fabrication does not only allow for avoiding the use of environmentally hazardous, toxic, and expensive organic solvents as well as the need for super-dry conditions up to the cell assembly, but moreover a facilitated recycling process due to the water-soluble binding agents. Additionally, of great importance with regard to the latter is the careful selection of the cathode chemistry – not least with respect to economic aspects. Herein, we summarize the results and progresses obtained within MARS-EV, highlighting their importance for the realization of environmentally friendly lithium-ion batteries for a sustainably electrified transportation.