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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.

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.

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.

The preparation and the structural, morphological and electrochemical characterization of a Silicon/V2O5 nanosheets composite (Si@V2O5), as an active anode material for Li-ion batteries, are here reported. The nanocomposite material, aimed at mitigating the morphological instability issues commonly plaguing Si-based anodes, is prepared by a H2O2-based low-impact synthesis, while the electrode processing involves the use of Polyacrylic Acid (PAA) binder. The electrolyte formulation is optimized as well, by employing Vinylene Carbonate (VC) additive, in order to maximize cycling stability and performance. Preliminary results report specific capacities of 932 mAhg−1 and 759 mAhg−1 after 50 cycles at 500 mA g−1 and 1000 mA g−1, respectively. The Si@V2O5 electrode also shows remarkable rate capability performance.

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

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

A graphene-based composite containing Sn and Sb is synthesized and characterized. Structural and morphological characterizations demonstrate the achievement of multilayer graphene with anchored SnSb nanoparticles. The composite is tested as active material for lithium-ion battery anodes and, as a result of the use of poly acrylic acid binder and vinylene carbonate electrolyte additive, remarkable electrochemical performance are achieved in terms of stable cycling stability and specific gravimetric capacity (468 mAh g−1 after 75 cycles with a capacity retention of about 80%). Moreover, impedance spectroscopy analysis further demonstrates the enhanced stability obtained by using, together with vinylene carbonate electrolyte additive, poly acrylic acid binder instead of poly vinylidene difluoride.

The electrochemical behavior of a composite anode based on tin oxide nanoparticles embedded in electrically conductive graphene matrix is reported. The composite has been synthetized through microwave reduction of poly acrylic acid functionalized graphene oxide and a tin oxide organic precursor both dispersed in ethylene glycol. The poly acrylic functionalization of graphene oxide partially prevent the re-stacking of the graphene layers. In addition, poly acrylic acid acts as a surfactant favoring an optimized dispersion of the metal and, after thermal decomposition, contributes in creating a carbon layer for an improved conductivity. The final product morphology reveals a composite in which SnO 2 nanoparticles are homogenously distributed into the reduced graphene oxide matrix. Graphene/SnO 2 nanocomposite electrodes, prepared using Super-P carbon as conducting additive and polyvinylidenedifluoride as binder, exhibit high rate capability and cycle life during galvanostatic charge/discharge tests. After more than 140 cycles, mostly performed at 500 mA g −1 , the electrodes show a remarkable stable specific capacity of about 430 mAh g −1 with a Coulombic efficiency close to 100%.The morphological stability of the electrode is also confirmed by impedance spectroscopy analysis, which shows solid-electrolyte interphase related resistance values constant up to 100 cycles.

The poor electrochemical performance of Li-ion batteries at low temperature is one of the major technical barriers to their practical application as energy sources. Here we report an attempt to improve the low-temperature electrochemical behavior of Li4Ti5O12 (LTO) anodes by replacing pristine Super-P with a Cu/Super-P composite in the electrodes composition. The composite, consisting of copper nanoparticles supported on Super-P carbon (Cu/Super-P), has been synthesized via a fast one-pot microwave-assisted polyol procedure. The comparison between the electrochemical performances of electrodes manufactured with pristine Super-P and of those that used the Cu/Super-P shows that the synthesized composite is indeed effective in enhancing the low-temperature electrochemical behavior of LTO anodes. Galvanostatic cycling demonstrates that much higher capacities are obtained within the investigated temperature range (from 20 to −30 °C), regardless of the applied C-rate. Furthermore, the study of the differential capacity plots clearly shows that lower polarization is achieved when the Cu/Super-P composite replaces pristine Super-P.

This paper describes the preparation and characterization of a high-voltage lithium-ion battery based on Sn-decorated reduced graphene oxide and LiNi0.5Mn1.5O4 as the anode and cathode active materials, respectively. The Sn-decorated reduced graphene oxide is prepared using a microwave-assisted hydrothermal synthesis method followed by reduction at high temperature of a mixture of (C6H5)2SnCl2 and graphene oxide. The so-obtained anode material is characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and electron diffraction spectroscopy. The LiNi0.5Mn1.5O4 is a commercially available product. The two materials are used to prepare composite electrodes, and their electrochemical properties are investigated by galvanostatic charge/discharge cycles at various current densities in lithium cells. The electrodes are then used to assemble a high-voltage lithium-ion cell, and the cell is tested to evaluate its performance as a function of discharge rate and cycle number. © 2015, Springer-Verlag Berlin Heidelberg.

International audience; Herein, we present the upscaled synthesis of nanoparticulate Li4Ti5O12 (LTO) by means of flame spray pyrolysis (FSP), yielding high phase purity and appropriate morphology for application as high-power lithium-ion anode material. Electrodes based on this optimized LTO nanopowder, carboxymethyl cellulose (CMC) as binder, and copper as current collector revealed excellent rate performance, providing specific capacities of 133, 131, 129, 127, 124, and 115 mAh g(-1) when applying C rates of 1C, 2C, 5C, 10C, 20C, and 50C, respectively. Targeting the commercial application of thus synthesized nanoparticles, we optimized also the electrode composition, comparing three different binding agents (CMC, PVdF, and poly(acrylic acid), PAA) and substituting the copper current collector by aluminum. The results of this comparative analysis show, that the combination of nanoparticulate LTO, CMC, and an aluminum current collector appears most suitable toward the realization of environmentally friendly and cost-efficient lithium-ion anodes, presenting very stable cycling performance for more than 1000 cycles at 10C without substantial capacity decay. (C) The Author(s) 2015. Published by ECS. All rights reserved.

A graphene/silicon nanocomposite has been synthesized, characterized and tested as anode active material for lithium-ion batteries. A morphologically stable composite has been obtained by dispersing silicon nanoparticles in graphene oxide, previously functionalized with low-molecular weight polyacrylic acid, in eco-friendly, low-cost solvent such as ethylene glycol. The use of functionalized graphene oxide as substrate for the dispersion avoids the aggregation of silicon particles during the synthesis and decreases the detrimental effect of graphene layers re-stacking. Microwave irradiation of the suspension, inducing reduction of graphene oxide, and the following thermal annealing of the solid powder obtained by filtration, yield a graphene/silicon composite material with optimized morphology and properties. Composite anodes, prepared with high-molecular weight polyacrylic acid as green binder, exhibited high and stable reversible capacity values, of the order of 1000 mAh g −1 , when cycled using vinylene carbonate as electrolyte additive. After 100 cycles at a current of 500 mA g −1 , the anode showed a discharge capacity retention of about 80%. The mechanism of reversible lithium uptake is described in terms of Li–Si alloying/dealloying reaction. Comparison of the impedance responses of cells tested in electrolytes with or without vinylene carbonate confirms the beneficial effects of the additive in stabilizing the composite anode.