Lithium Ion Intercalation Research Articles

Battery Adaptive Observer for a Single-Particle Model With Intercalation-Induced Stress

Battery electrode particle fracture due to stress generation is a critical mechanism causing capacity fade, and thus reducing battery life. This paper develops a nonlinear adaptive observer for lithium-ion battery state of charge (SOC), electrode particle stress, and solid phase diffusivity estimation using a high-fidelity coupled single particle—mechanical stress model, where the stress submodel captures stress development during lithium-ion intercalation and deintercalation. Simultaneous state and parameter estimation based on coupled single particle and mechanical stress model is extremely challenging because the coupled model is given by highly nonlinear partial differential equations. We address this problem by reducing the coupled model to a nonlinear finite dimensional system. The key novelty of this paper is a nonlinear internal state and parameter estimation methodology, from which the internal stress and the state of health-related parameters are monitored from real-time electric current and terminal voltage measurements. Numerical studies on simulation and experimental data have been conducted to illustrate the performance of the proposed estimation scheme.

Lithium Ion Intercalation into Graphite in so2-Based Inorganic Electrolyte Towards High-Rate Capable and Safe Lithium Ion Batteries

Lithium ion batteries (LIBs) have been used widely as power sources for portable electronic devices and regarded as promising power sources for next-generation secondary battery system. To meet the demands of these emerging applications, the safety, power density and energy density of Li batteries need to be further improved. In this presentation, we report the reversible lithium ion intercalation reaction into graphite anode in LiAlCl4-3SO2 non-flammable inorganic liquid electrolyte. Using ex situ x-ray diffraction analysis as well as electrochemical characterization techniques, we found that lithium ions could be reversibly intercalated into graphite anode materials with highly stable capacity retention up to 100 cycles. X-ray photoelectron spectroscopy on the reacted graphite electrode clearly showed that solid electrolyte interface(SEI) formed on the graphite was completely different from SEI formed on the graphite in the conventionally used organic electrolyte. Detailed electrochemical properties of graphite in SO2-based inorganic electrolyte will be discussed in this presentation.

Electrochemical Properties of Petroleum Coke As Active Material of Negative Electrode in Lithium Batteries

The possibility of usage of petroleum coke as active materials of negative electrodes in lithium batteries was studied in presented work. Studies show that crude petroleum coke has high specific resistance (1.4·107 Ohm·cm), that is in 7 times greater than the resistance of graphite (0.5-1.0 Ohm·cm), used as the active material of negative electrodes in lithium-ion batteries. Thermal treatment of crude petroleum coke at 800 °C in the atmosphere of air or nitrogen during 5 hours decreases the specific resistance to 1.3 and 1.5 Ohm·cm, correspondingly, and increases their specific surface area from <0.1 m2/g to 5.3 m2/g (nitrogen) and 0.7 m2/g (air). Specific surface area was estimated by sorption of dyes (methyl orange).Crude petroleum coke is not electrochemical active and can not be DC cycled (Figure). Heat treatment of petroleum coke, both in the atmosphere of air and in the atmosphere of nitrogen, leads to the appearance of electrochemical activity and the ability to reversibly intercalate lithium ions. At DC cycling of electrodes based on heat-treated petroleum coke in the range of voltage of 0 - 1.0 V vs Li/Li+ the reversible capacity is 300-350 mA·h/g.The shapes of charge and discharge curves (Figure) of semi-cells with electrodes based on petroleum coke are similar to the charge-discharge curves of semi-cells with electrodes based on structurally disordered carbons. This work was performed as part of the Government Order to Ufa Institute of Chemistry of the Russian Academy of Sciences by the Ministry of Science and Higher Education of the Russian Federation (Theme No. AAAA-A17-117011910031-7). Figure 1

(Invited) Strategies for Achieving High-Energy Density Storage Systems

Energy storage is vital for driving an energy independent world economy currently largely dependent on exploiting natural reserves supplemented by oil and gas exports. The field of Li-ion batteries has witnessed tremendous progress since the commercialization of the first Li-ion battery (LIB) by Sony in 1991. Correspondingly, there has been tremendous progress in the areas of cathode, electrolytes as well as anodes [1]. The area of lithiated transition metal oxides despite much advances, are still the flagship cathode systems largely focused on intercalation chemistry. However, the last two decades witnessed exploration of newer chemistries exploiting alloying and zintl phase formation focusing on silicon and tin as alternative anodes. Similarly, there has been tremendous research in the area of alternative energy storage systems beyond lithium-ion intercalation chemistry. Lithium-sulfur batteries (LSB) and Li metal anodes have accordingly emerged in the forefront and have been the spotlight of much research activity in recent years. All the systems are unfortunately, plagued by intransigent inferior electronic conductivity and voltage-specific phase transition related kinetic limitations accompanied with ensuing chemical, physical, and electrochemical challenges. Nano-engineered approaches coupled with the concomitant progress made in science and technology of synthetic and analytical materials chemistry appear primed for overcoming these hurdles. We have thus far, implemented dynamic theoretical and experimental strategies to develop engineered electronic and Li-ion conducting nanomaterials showing considerable promise as supporting components augmenting the performance and overcoming many of the limitations affecting these systems. Additionally, we have developed several approaches utilizing nanoscale droplets, nanoparticles, hollow Si nanotubes (h-SiNTs), cost-effective template derived nanoscale morphologies, scribable and flexible hetero-structured architectures displaying impressive capacities as high as ~3000 mAh/g with sustained cyclability and high rate capability in Si anodes[2]. Electrochemical approaches have also been developed for generating binder-less silicon based thin film anodes with considerable promise. Similarly, engineering approaches were implemented for generating sulfur cathodes in LSBs exploiting the tailored attributes of inorganic, nanocomposite, tethered, and polymeric lithium ion conducting (LIC) coupled with chemical framework materials (CFM) based matrices for encapsulating sulfur along with novel fine yarn-like and tethered architectures yielding 5.5 mAh/cm2 – 12 mAh/cm2 areal capacity as well as ~1200 mAh/g specific capacity with sulfur loadings as high as 20 mg/cm2 displaying up to 250 cycles cycling stability [3, 4]. New materials were identified serving as novel dendrite free anodes. Engineering strategies were also developed for stabilizing the Li metal anodes preventing and eliminating dendrite formation. These systems together have been studied as alternative safe anodes to the currently used Li metal anodes. Results of these studies will be presented and discussed. The presentation will also provide an insight into the promising future in store for generating tailored functional engineered systems in the rapidly evolving digitally savvy era of the 21st century as a pathway to potentially achieving energy independence in the near future. References Wang, P.N. Kumta, et al. ACS Nano (2011);Gattu, P.N. Kumta et al. Nano Research (2017)M. Shanthi, P.N. Kumta et al. Electrochimica Acta (2017)M. Shanthi, P.N. Kumta et al. Applied Energy Materials (2018)

Fast precipitation-induced LiFe0.5Mn0.5PO4/C nanorods with a fine size and large exposure of the (010) faces for high-performance lithium-ion batteries

Olivine-type LiFexMn1-xPO4/C cathode materials are of great interest for lithium-ion batteries because of their higher lithium ion intercalation potential compared with that of LiFePO4. Two types of LiFe0.5Mn0.5PO4/C nanorods with different sizes and crystal structures were synthesized through a facile glycol-based solvothermal process with different precursor feeding sequences. The microstructural investigation revealed that the size and structure of the LiFe0.5Mn0.5PO4 nanorods can be tuned by nucleation and crystal growth rates of the intermediate precipitates, which can be controlled by precursor feeding sequence. The LiFe0.5Mn0.5PO4 nanorods obtained through the first feeding sequence (a solution of transition metal salts was added dropwise into the solution mixture of LiOH and H3PO4) exhibited less exposure of the (010) crystal faces and had bigger sizes compared with those of the LiFe0.5Mn0.5PO4 nanorods obtained through the second feeding sequence (a LiOH solution was added dropwise into the solution mixture of H3PO4 and transition metal salts). Electrochemical investigations indicated that the LiFe0.5Mn0.5PO4 nanorods obtained through the second feeding sequence showed substantially improved electrochemical performance, in which the discharge capacities reached 157 and 119 mAh g−1 at 0.2 and 5 C, respectively. Furthermore, a capacity retention of 89% was obtained after 500 cycles at 1 C, demonstrating excellent cyclic stability.

Topological optimization of patterned silicon anode by finite element analysis

A silicon-based anode in lithium-ion battery exhibits several times higher gravimetric energy storage capacity compared to an established carbon-based anode. However, the cycling performance of the silicon anode is poor due to the extremely large volume variation during the intercalation of lithium ions. The micro-structuring of silicon facilitates cycling performance. In particular, patterned microstructures are discussed as a possible solution. The large volumetric change can be adopted in such structures by bending walls and rotation around fixed vertexes. Nevertheless, the cycling performance of known patterned anodes remains poor due to plastic deformations. In this paper, a new square-based-patterned silicon anode is proposed and analyzed using the finite element method. The maximal stress in the topologically optimized structure is below the yield strength of lithiated silicon. In contrast to known structures, the deformed pattern of the new structure is explicitly defined by its initial geometry. A similar modification of the honeycomb-based-patterned anode leads to a slightly larger bending stress, but still below the yield stress of lithiated silicon. The related pure elastic deformation behavior is favorable to a prolonged cycling life of the micro-structured silicon anode. The developed approach can be applied for analysis of other severely swelling metamaterials.

In-Situ Synthesized Si@C Materials for the Lithium Ion Battery: A Mini Review.

As an important component, the anode determines the property and development of lithium ion batteries. The synthetic method and the structure design of the negative electrode materials play decisive roles in improving the property of the thus-assembled batteries. Si@C compound materials have been widely used based on their excellent lithium ion intercalation capacity and cyclic stability, in which the in-situ synthetic method can make full use of the structural advantages of the monomer itself, thus improving the electrochemical performance of the anode material. In this paper, the different preparation technologies and composite structures of Si@C compound materials by in-situ synthesis are introduced. The research progress of Si@C compound materials by in-situ synthesis is reviewed, and the prospect of future development of Si@C compound materials has been tentatively commented.

Cover Feature: Extended Limits of Reversible Electrochemical Lithiation of Crystalline V2O5 (ChemElectroChem 7/2019)

The Cover Feature shows the intercalation of lithium ions into vanadium oxide covered with reduced graphene oxide. Uniform electron transport in such material extends the limits of V2O5 reversible electrochemical lithiation. More information can be found in the Article by D. M. Itkis et al. on page 2013 in Issue 7, 2019 (DOI: 10.1002/celc.201801638).

Chitosan complements entrapment of silicon inside nitrogen doped carbon to improve and stabilize the capacity of Li-ion batteries

A facile strategy to entrap milled silicon (m-Si) particles using nitrogen-doped-carbon (N-C@m-Si) to overcome the dramatic volume changes in Si during intercalation of lithium ions and to improve its electronic conductivity is reported here. The only natural nitrogen containing biomaterial alkaline polysaccharide, i.e., chitosan, is used as the carbon source. Simple hydrothermal technique followed by a subsequent carbonization process is used to synthesize N-C and N-C@m-Si particles. N-C@m-Si exhibited significantly improved electrochemical performance as compared to bare m-Si, which is confirmed by the obtained discharge capacity of 942.4 mAh g−1 and columbic efficiency of 97% after 50 cycles at 0.1C rate. With regard to the N-C electrodes, the obtained discharge capacity of 485.34 mAh g−1 and columbic efficiency of 99.78%, after 50 cycles at 0.1C rate is superior to the commercial graphite electrodes. The solid electrolyte interphase (SEI) layer that formed over m-Si and N-C@m-Si electrodes is characterized using X-ray photoelectron spectroscopy. Compared to the SEI layer that formed over m-Si electrode after 10 charge-discharge cycles, the N-C@m-Si electrode had a stable lithium fluoride and carbonate species. Brief reaction mechanisms, representing the formation of different species in the SEI layer, is derived to explain its behavior during the electrochemical processes.

Performance of TiO2 Fibers Prepared by Electrostatic Spinning As Lithium-Ion Battery Anode Material

This paper reports a one-dimensional (1D) TiO2 nanostructure with significantly enhanced conductivity. Anatase TiO2 with a 1D nanostructure was successfully prepared by the electrostatic spinning method, and the effect of calcination temperature on its electrochemical performance was studied. The samples prepared at different calcining temperatures (400, 450, and 480°C) were analyzed by physical and electrochemical methods to identify the optimal heat-treatment conditions. Temperature was found to be another important factor influencing the electrochemical performance of 1D materials besides their structure and morphology. The anatase TiO2 calcined at 450°C had a discharge capacity of 192.8 mA h g–1 at 0.2 C with over 96% capacity retention after 100 cycles. The improved lithium-ion intercalation properties of the rod-shaped TiO2 might be attributed to the relatively large specific surface area, short transport distance of the 1D structure, and freedom for the volume change accompanying lithium-ion intercalation.

Recent Developments in the Effects of Different Dopants on the Structure and Property of Lithium Titanate Material

The lithium titanium spinel Li4Ti5O[Formula: see text] has attracted more and more attention as anode materials applied in lithium ion batteries. Li4Ti5O[Formula: see text] material has been found to be able to intercalate lithium ions without deformation of the lattice. However, compared with graphite and other anode materials, the low conductivity of Li4Ti5O[Formula: see text] restricts its charging and discharging rate. Doping is deemed to be a businesslike method to enhance ionic and electronic conductivity of Li4Ti5O[Formula: see text]. This paper reviews the effects of Li4Ti5O[Formula: see text] with different doping ions on different crystal lattice states. And it has been found by a summary that the doping objective of doping ions at Li4Ti5O[Formula: see text] is also different. Moreover, the applications of ion doping in different fields of Li4Ti5O[Formula: see text] are prospected.

Fe3C-doped asymmetric porous carbon membrane binder-free integrated materials as high performance anodes of lithium-ion batteries

In traditional pulverous electrodes, the severe volume expansion that occurs during the intercalation and de-intercalation of lithium ions causes the active material to agglomerate and pulverize, eventually leading to active material that deviates from the current collector and result in poor electrochemical performances. Therefore, a new kind of Fe3C-doped asymmetric porous carbon membrane (Fe3C/APCM) binder-free integrated electrode materials is proposed by using a simple phase inversion method. The Fe3C/APCM electrodes that are obtained act as both active materials and current collector, saving the use of current collectors, conductive agents and binders. The effects of temperature and thickness on the conductivity and diffusion of ions are investigated, confirming the optimum temperature and thickness of the casting membrane solution to be 800 °C and 100 μm (Fe3C/APCM-100), respectively. Abundant finger-shaped and honeycomb-like pores are formed in the Fe3C/APCM-100, effectively accommodating the volume changes induced by the charge-discharge process. The specific surface area of the electrode materials reaches to 134.9 m2 g−1, enhancing the connection between active materials and electrolytes, leading to a high rate of electron transfer and ion diffusion. As the anode materials of a lithium-ion battery, the Fe3C/APCM-100 composites achieve an excellent rate capability and long cycling stability. The rate capability reaches to 605.5 mAh g−1 at a current density of 0.1 A g−1, and 601.0 mAh g−1 is retained when the current density returns to 0.1 A g−1. Even at a high current density of 1.0 A g−1, an excellent cyclic capacity of 212.9 mAh g−1 is still achieved after 200 cycles. No obvious structural and morphological changes are observed in SEM images of Fe3C/APCM-100 electrodes before and after a charge-discharge process. Fe3C/APCM is promising as an anode material for lithium-ion batteries.

Crystal chemistry and lithium-ion intercalation properties of lithium manganese silicate cathode for aqueous rechargeable Li-ion batteries

Lithium manganese silicate (Li2MnSiO4) demonstrates rich polymorphism with orthorhombic Pmn21 polymorph having better crystalline ordering over orthorhombic Pmnb and monoclinic forms. In this work, Li2MnSiO4 nanoparticles with the Pmn21 phase were synthesized by hydrothermal synthesis. Powder X-ray diffraction, HRSEM, and HRTEM as well as SAXS investigations revealed crystalline, spherical nanoparticles with average diameters between 14 and 25 nm. The binding energy of surface active Mn2+ ions in Li2MnSiO4 was observed at 642.9 eV in XPS analysis. SSNMR spectroscopic results revealed isotropic peaks at − 288.5 and 295.32 ppm which are attributed to the hyperfine coupling between the Li nuclei and the unpaired electrons of the Mn2+ ions. The electrochemical properties of Li2MnSiO4 electrode were studied in various 1 M LiX (X = SO42−, NO3− and ClO4−) aqueous electrolytes at a potential window of 0.2–1 V. Studies in the Li2SO4 aqueous electrolyte demonstrated better electrochemical properties with increasing peak current values up till the 2000th cycle. Charge and discharge capacities of 77.0 and 57.7 mAh g−1 were obtained at a scan rate of 5 mV s−1 with a Li-ion diffusion coefficient of 1.61 × 10−16 cm2 s−2. A small charge transfer resistance in the Li2SO4 electrolyte was also observed in EIS measurements indicating faster charge transfer kinetics. An aqueous Li-ion Swagelok-type full cell was assembled with microcrystalline graphite as anode and Li2MnSiO4 as the cathode. 1 M Li2SO4 was used as the electrolyte. The cell delivered a charge capacity of 61.8 mAh g−1 and a discharge capacity of 52.5 mAh g−1 at a current load of 1.2 A g−1 with good capacity retention of 94.0% and a Coulombic efficiency of 99.5% over 3300 cycles. SEM image, FTIR, XPS, and discharge capacity versus coulombic efficiency plots of Li2MnSiO4 nanoparticles

Diagnostics of lithium-ion intercalation rate-determining step: Distinguishing between slow desolvation and slow charge transfer

The elucidation of the reaction rate-determining step nature in intercalation processes is essential for the development of approaches for the precise control of rate-limiting factors. In this work, we explore the kinetic patterns of lithium-ion intercalation into two model cathode materials (LiCoO2 and LiMn2O4) and develop criteria for distinguishing between Butler-Volmer slow charge transfer and slow chemical steps. A numerical model for the rate-limiting ion desolvation step is developed and the predictions of the model are compared with the experimental voltammetric and electrochemical impedance spectroscopy data. We show that slow desolvation step results in essential changes in the shape of both cyclic voltammetry and impedance responses with the kinetic resistance vs. potential dependencies being highly informative for the reaction rate control diagnostics. The consideration of the intercalation kinetics in four solvents (water, propylene carbonate, acetonitrile and dimethyl sulfoxide) allows concluding on the influence of the resistivity of surface layer/electrode material interface on the reaction slow step nature.

A carbonate-free electrolyte for lithium-ion batteries based on lithium bis(fluorosulfonyl)imide and 2-methylglutaronitrile enabling graphite negative electrodes

We report here a carbonate-free electrolyte for lithium-ion batteries with low flammability which consist of lithium bis(fluorosulfonyl)imide (LiFSI) and 2-methylglutaronitrile (MGN) (LiFSI/MGN). LiFSI/MGN enables reversible lithium ion intercalation into graphite without any additives or co-solvents due to LiFSI and MGN-derived SEI formed on the surface of graphite negative electrode. LiCoO2/graphite full-cells with LiFSI/MGN show good cycle stability even at 1C despite its low ionic conductivity and high viscosity while those with LiFSI/succinonitrile (SN) and lithium bis(trifluorosulfonyl)imide (LiTFSI)/SN exhibit capacity fade. Moreover, LiFSI/MGN shows stable liquid phase at low temperature owing to its branched structure. Thus, LiFSI/MGN opens the possibility of lithium-ion batteries with enhanced safety owing to the high thermal stability and low flammability of MGN.

Lithium-Ion Intercalation into Graphite in SO2-Based Inorganic Electrolyte toward High-Rate-Capable and Safe Lithium-Ion Batteries.

Herein, we have identified that lithium ions in an SO2-based inorganic electrolyte reversibly intercalate and deintercalate into/out of graphite electrode using ex situ X-ray diffraction and various electrochemical methods. X-ray photoelectron spectroscopy shows that the solid electrolyte interphase on the graphite electrode is mainly composed of inorganic compounds, such as LiCl and lithium sulfur-oxy compounds. Graphite electrode in SO2-based inorganic electrolyte has stable capacity retention up to 100 cycles and outstanding rate capability performance. This can be attributed to low interfacial impedance and high ionic conductivity of SO2-based inorganic electrolyte, which are superior to those of conventional organic electrolytes. Considering the remarkable rate capability and intrinsically nonflammable properties of the electrolyte, use of graphite and an SO2 electrolyte will likely facilitate the development of advanced lithium-ion batteries.

Hydrothermal Synthesis of Cellulose-Derived Carbon Nanospheres from Corn Straw as Anode Materials for Lithium ion Batteries.

As a most attractive renewable resource, biomass has the advantages of low pollution, wide distribution and abundant resources, promoting its applications in lithium ion batteries (LIBs). Herein, cellulose-derived carbon nanospheres (CCS) were successfully synthesized by hydrothermal carbonization (HTC) from corn straw for use as an anode in LIBs. The uniform distribution and cross-linked structure of carbon nanospheres were obtained by carefully controlling reaction time, which could not only decrease the transport pathway of lithium ions, but also reduce the structural damage caused by the intercalation of lithium ions. Especially, obtained after hydrothermal carbonization for 36 h, those typical characteristics make it deliver excellent cycling stability as well as the notable specific capacity of 577 mA h g−1 after 100 cycles at 0.2C. Hence, this efficient and environment-friendly method for the fabrication of CCS from corn straw could realize the secondary utilization of biomass waste, as well as serve as a new choice for LIBs anode materials.

The Effect of Electrolyte Type on the Li Ion Intercalation in Copper Hexacyanoferrate

Copper hexacyanoferrate (CuHCFe) is proved to be a potential cathode for potassium ion and sodium ion storage in aqueous system recently. However, its ability for lithium ion storage has not been well studied. Here, we synthesized CuHCFe by a low-cost and scalable co-precipitation method, and its electrochemical behavior as the cathode for lithium ion storage was investigated both in aqueous and organic systems. The CuHCFe electrode shows larger capacity and better rate capability in organic system compared with the performance in aqueous system. In addition, the capacity has 88% retention after 500 cycles. We further analyzed the strain generated during lithium ion intercalation by ex-situ X-ray diffraction (XRD) method in both types of electrolyte. The lattice of CuHCFe shows shrinkage with ion intercalation in both systems. The measured strains are 0.70% and 0.83% in aqueous and organic system, respectively. The results indicate that the large open framework and small strain are the essential factors for the promising electrochemical performance.

Lithiation-Aided Conversion of End-of-Life Lithium-Ion Battery Anodes to High-Quality Graphene and Graphene Oxide.

In the past two decades, lithium-ion (Li-ion) batteries have transformed the appearance of the world. Along with the ever-increasing production and usage are the tremendous number of retired batteries, which have created social and environmental issues, making battery recycling an urgent task. Graphene has exhibited outstanding electronic and mechanical properties but it is still difficult to fabricate high-quality graphene with feasible procedures at low cost. Here, a strategy of smartly converting retired Li-ion battery anodes to graphene and graphene oxide is proposed. The graphite powders collected from end-of-life Li-ion batteries exhibited irregular expansion because of the lithium-ion intercalation and deintercalation in the anodegraphite during battery charge/discharge. Such prefabrication process facilitated both chemical and physical exfoliations of the graphite. Comparing with the graphene oxide derived from pristine, untreated graphite, the graphene oxide from anodegraphite exhibited superlative homogeneity and electrochemical properties. The lithiation aided pre-expansion enabled 4 times enhancement of graphene productivity by shear mixing. Furthermore, the graphene fabrication was seamlessly inserted into the currently used battery recycling streamline in which the acid treatment was found to further swell the graphite lattice, pushing up the graphene productivity to 83.7% (10 times higher than that of pristine graphite powders). The findings create new opportunities for capitalizing on waste batteries to produce high-quality graphene and its derivatives.

Facile method to synthesis hybrid phase 1T@2H MoSe2 nanostructures for rechargeable lithium ion batteries

Energy storage devices have become vital parts of our routine life. Among the numerous candidates, lithium ion batteries are considered the most favorable energy storage systems. MoSe2 consists of Se–Mo–Se atom layers bounded with van-der Waals forces and is highly favored for lithium ion intercalation and extraction. This paper establishes a simple and economical one-pot chemical method to synthesize MoSe2 nanostructures for lithium ion battery anode material. Raman scattering confirmed the 1T@2H MoSe2 mixed phase structure, transmission electron microscopy showed 2H and 1T phase contours in the MoSe2 nanosheet, and scanning electron microscopy showed the nanograin honeycomb structured morphology. The 1T@2H MoSe2 nanostructures deliver enhanced primary discharge capacity 843 mAh/g at 100mA/g with 99% Coulombic efficiency after 100cycles. Electrochemical results confirmed the 1T@2H MoSe2 nanostructure would be an excellent anode material and a promising candidate for high performance lithium ion batteries.