Lithium Deintercalation Research Articles

Ab initio study on changing behaviors of lithium-rich layered composite cathode materials

The lithium-rich composite-layered oxide, xLi2MnO3•(1-x)LiM'O2, where M’ represents transition metals, is a promising cathode material with excellent capacity at high working voltage for lithium-ion batteries (LIBs). Nevertheless, an unusual charge-discharge feature is observed for this material with sloping and plateau regions during the initial charging. In this work, ab initio calculations based on density functional theory were employed to examine the stability of xLi2MnO3•(1-x)Li(Ni1/3Co1/3Mn1/3)O2 composite-layered cathode materials during the first charging. Optimized atomistic models for different compositions (x = 0.0, 0.3, 0.4, 0.5, 0.7, and 1) unveil a pseudo-rhombohedral or monoclinic-like structure within the solid solution phase, with simulated X-ray diffraction patterns closely matching experimental data. Using these atomistic models, the first charging process of the 0.4Li2MnO3•0.6Li(Ni1/3Co1/3Mn1/3)O2 cathode were investigated. There exists phase transition from a layered to a spinel structure. Additionally, Bader charge analysis reveals intriguing trends during the first delithiation process, where the valence states of Ni and Co gradual increase, while that of Mn almost remains unchanged. Simultaneously, significant oxidation of O is observed. This finding leads to further evaluations on oxygen vacancy formation in comparison to the energy required for delithiation. Defect formation energy calculations demonstrate that the plateau in charging curve is resulted from oxygen vacancy formation during the first charging. By empirical fitting oxygen chemical potential at μO = -1.200 eV, the calculated charging-discharging curves aligned well with experimental data during the first and second charging. Furthermore, the pathways of lithium and oxygen deintercalation are elucidated. This work contributes fundamental understandings on the xLi2MnO3•(1-x)LiM'O2 composite-layered oxides as cathode for LIBs, providing valuable guidance for further developments in high-capacity Co-lean cathode materials.

Boosting Li-ion storage kinetics via constructing layered TiO2 anode

Due to the typical intercalation-deintercalation mechanism, TiO2 holds great promise as a sustainable anode for next-generation lithium-ion batteries (LIBs). However, commercial TiO2 (C–TiO2) is granular and shows slow ionic conductivity, which greatly hinders its development due to sluggish kinetics, leading to low reversible capacity and inferior rate capability. In this study, a two-dimensional layered TiO2 (L-TiO2) anode is prepared via a one-step calcination process, which can effectively shorten the lithium ions diffusion path and improve its lithium ions conductivity. We elucidated the enhanced electrochemical performance of L-TiO2 as an anode in LIBs through pseudocapacitive acceleration of lithium ions intercalation and deintercalation using various characterization techniques, including different scan rate cyclic voltammetry tests, in situ electrochemical impedance spectroscopy, in situ Raman spectroscopy, and in situ X-ray diffraction. In comparison to C–TiO2 material, L-TiO2 material showcases remarkable electrochemical performance, achieving a capacity of 166 mAh/g after 100 cycles at 0.1 C. Additionally, the lithium-ion diffusion coefficient calculated for the L-TiO2 is two orders of magnitude greater, underscoring its potential as a negative electrode material for LIBs.

Nano-alumina islands enabling superior capacitive lithium-ion storage of pitaya configuration

Currently, high-temperature thermal failure hinders the development of lithium-ion batteries (LIBs). Interfacial side reaction of electrolyte and electrode is the main cause of thermal failure at high temperature. Explicitly, suppressing interfacial side reactions at high temperatures can help the research of capacitive energy storage electrodes. While, thermo-electrochemical inert alumina can be facilitated to solve this problem. In this paper, pitaya configuration of nano-alumina islands uniformly dispersed in carbon matrix can be achieved from NOTT-300(Al). Nano-alumina contributes to the structural stability of porous carbon during carbonization and lithium deintercalation. And nano-alumina islands are effective in suppressing interfacial side reactions at high temperatures. Thus, NC-3 exhibits competitive specific capacity (717.1 mAh/g) and cycling stability (99.15% after 500 cycles). NC-3's capacity was confirmed to be mainly attributed to capacitive energy storage mechanism. This study provides a new research paradigm for nano-alumina to improve the high-temperature thermal stability management of LIBs.

Graphene oxide assisted preparation of V2O5 films for electrochromic and energy storage applications

A V2O5 film is prepared by an electrochemical deposition method with the assistance of graphene oxide (GO). The surface morphology and microstructure of the film are characterized by scanning electron microscope, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy measurements. The results demonstrate that the prepared film is mainly composed of orthorhombic α-V2O5 with a small amount of tetragonal β-V2O5; the V2O5 film has a wrinkled surface morphology and contains a certain low valance V4+ and a trace amount of graphene oxide residue. The V2O5 film exhibits good lithium storage activity and excellent cycling stability (with a capacity retention rate of 93.6% after 500 cycles at 0.5 mA cm−2). During lithium intercalation and de-intercalation processes, the color of the V2O5 film changes reversibly from yellow to green, and finally blue, with a fast response time (6∼9 s) and high coloration efficiency (19.77 cm2 C−1). In addition, the electrochromic device assembled with the V2O5 film as the electrochromic layer, NiHCF as the ion storage layer, and 1 M LiClO4/propylene carbonate solution as the electrolyte also exhibits excellent cycling stability, suggesting the significant potential of this V2O5 film for electrochromic and energy storage applications.

Surface Degradation of NMC Electrodes Exposed to Air and Impact on Subsequent Cycling

To meet the ambitious international emissions commitments laid out in the Paris climate agreement making the transition of society from being dependent on fossil fuels towards increased use of renewable energy sources possible, lithium-ion batteries (LIBs) are a key enabling technology. Even though LIBs are already extensively used in portable electronics and the rapidly expanding market of hybrid- and full-electric vehicles, more extensive deployment requires longer cycle-lifetimes, enhancements in energy density, and reductions in cost. In electric vehicles one of the most common materials for the positive electrodes is based on the lithium nickel manganese cobalt oxide (LixNi1-y-zMnyCozO2, NMC) compound with different ratios of transition metals. The NMC materials are well known for consisting of reasonably abundant materials, their high energy density and good cyclebility. In order to decrease the price while also further improving the energy density, it has become more popular during the last few years to increase the nickel content, being responsible for the redox process thereby contributing to a larger capacity. By increasing the nickel content, the quantity of cobalt required will decrease further, reducing the price. However it is also well known that in materials where the nickel content is high the surface side reactions will be augmented leading to more degradation and shorter cycle life. A high nickel content will not only affect the electrochemical side reactions during cycling, it has also been found that as NMC materials are exposed to air they will react differently, with more reactions for the nickel rich materials.It has been found that the NMC can react with H2O to form a LiOH layer and that once the layer is thick enough further side reactions would be prevented.1 It was assumed that the passivation was caused by the deintercalation of lithium, where the thin disordered rock salt layer would mitigate the Li+-water reactions through decreasing the amount of lithium deintercalation.1 Furthermore, the surface impurities formed during the air exposure have been observed to directly impact electrochemical performance during the first couple of cycles. Hatsukade et al. used isotopic labelling in order to measure the CO2 formation during the first cycles originating from the oxidative decomposition of these impurities.2 Air exposure has been shown to affect not only the first few cycles but also long term cycling as well.3 The degradation of the NMC has been found to be caused by phase transformation into rock salt and spinel structure, leading to nickel reduction and as a result formation of inter granular cracks, eventually leading to isolation of the active particles and increased charge transfer resistance.4 In this study the surface interactions at NMC electrodes during air exposure will be presented, showing both how the interactions take place as well as how the air exposure will affect the electrode-electrolyte interfaces during cycling. The NMC surface is analysed by x-ray photoelectron spectroscopy (XPS), photoemission electron microscopy (PEEM) and x-ray absorption spectroscopy (XAS). Zou, L. et al. Unlocking the passivation nature of the cathode–air interfacial reactions in lithium ion batteries. Nat. Commun. 11, (2020).Hatsukade, T., Schiele, A., Hartmann, P., Brezesinski, T. & Janek, J. Origin of Carbon Dioxide Evolved during Cycling of Nickel-Rich Layered NCM Cathodes. ACS Appl. Mater. Interfaces 10, 38892–38899 (2018).Meatza, I. De, Landa-medrano, I., Sananes-israel, S. & Eguia-barrio, A. Powder and Electrodes on the Electrochemical Performance in Li-ion Technology. Batteries 8, 1–18 (2022).Busà, C., Belekoukia, M. & Loveridge, M. J. The effects of ambient storage conditions on the structural and electrochemical properties of NMC-811 cathodes for Li-ion batteries. Electrochim. Acta 366, (2021).

Passivated Bi2Se3 electrode in Na2CO3 solution to improve anode efficiency in aqueous Li-ion batteries

Efficient anode materials are crucial for the success of aqueous rechargeable lithium-ion batteries (ALIBs) since many materials degrade significantly during electrochemical reactions. In this study, the modification of Bi2Se3 with Na2CO3 was explored to enhance the charge–discharge characteristics of the anode. The passivated Bi2Se3 electrode exhibited improved electrochemical performance, maintaining high charge and discharge capacities of 816 mAh·g−1 after the 5th cycle and 570 mAh·g−1 after the 100th cycle with stable Coulombic efficiency of 98.0 ± 1.2 %. Charge-discharge profiles and cyclic voltammetry revealed the lithium intercalation and deintercalation, while impedance spectroscopy indicated changes in the electrode structure during cycling. These findings highlight the potential of using Bi2Se3 electrodes with a pre-formed surface film to enhance the stability and performance of ALIBs.

Phase Chemistry for Hydration Sensitive (De)intercalation of Lithium Aluminum Layered Double Hydroxide Chlorides.

Lithium aluminum layered double hydroxide chlorides (LADH-Cl) have been widely used for lithium extraction from brine. Elevation of the performances of LADH-Cl sorbents urgently requires knowledge of the composition-structure-property relationship of LADH-Cl in lithium extraction applications, but these are still unclear. Herein, combining the phase equilibrium experiments, advanced solid characterization methods, and theoretical calculations, we constructed a cyclic work diagram of LADH-Cl for lithium capture from aqueous solution, where the reversible (de)hydration and (de)intercalation induced phase evolution of LADH-Cl dominates the apparent lithium "adsorption-desorption" behavior. It is found that the real active ingredient in LADH-Cl type lithium sorbents is a dihydrated LADH-Cl with an Al:Li molar ratio varying from 2 to 3. This reversible process indicates an ultimate reversible lithium (de)intercalation capacity of ∼10 mg of Li per g of LADH-Cl. Excessive lithium deintercalation results in the phase structure collapse of dihydrated LADH-Cl to form gibbsite. When interacting with a concentrated LiCl aqueous solution, gibbsite is easily converted into lithium saturated intercalated LADH-Cl phases. By further hydration with a diluted LiCl aqueous solution, this phase again converts to the active dihydrated LADH-Cl. In the whole cyclic progress, lithium ions thermodynamically favor staying in the Al-OH octahedral cavities, but the (de)intercalation of lithium has kinetic factors deriving from the variation of the Al-OH hydroxyl orientation. The present results provide fundamental knowledge for the rational design and application of LADH-Cl type lithium sorbents.

Application of two-dimensional lamellar lithium titanate in lithium-ion anode batteries

Lithium titanate exhibits effective suppression of lithium metal plating and lithium dendrite formation, attributed to its high lithium ion diffusion coefficient and a relatively high discharge plateau of 1.55 V (vs. Li+/Li). It is considered a zero-strain material, displaying minimal lattice size changes during lithium intercalation and deintercalation processes. The focus of this study was to obtain titanium dioxide through the calcination of selected MXene (Ti2C), and then mix it with lithium carbonate in a specific lithium-titanium ratio to generate lithium titanate. Spinel lithium titanate synthesized via solid-state method retained the sheet-like structure and excellent conductivity characteristics of MXene. Because its sheet structure provides a larger specific surface area for the electrode and enhances ion migration, it shows excellent electrochemical performance. The reaction mechanism was studied by in-situ Raman and variable speed CV. It was found that the reaction mechanism was pseudocapacitance plus lithium ion deintercalation. The obtained structure exhibited excellent electrochemical performance, making it suitable for applications in lithium-ion batteries.

Targeted electro-redox facilitating efficient delithiation of lithium manganese ion-sieve selective electrode

The electrically switched ion exchange (ESIX), as the most promising technique for the efficient extraction of lithium from brine, especially the lithium manganese ion-sieve membrane electrode, possesses the advantages of high selectivity, high adsorption capacity, and high stability. And to enable the simultaneous lithium intercalation and de-intercalation at the cathode and anode, respectively, the selective electrode ought to be delithiated before use. Traditional chemical and electrochemical delithiation and electrochemical techniques consume enormous amounts of reagents and energy, respectively. Thermodynamics and electrochemical analysis indicated that the cathodic reaction induced the high cell voltage, which in turn caused the emitting of toxic gases and high energy consumption. Thus, in this study, a targeted-redox system was adopted to alleviate the above problems. By adding excessive Cu2+ into the cathode compartment, the cell voltages in 5 h reduced from 3 V to about 1.5 V and further reduced to 1.2 V if diluted HCl was also added. With lower cell voltage and higher current density, a higher delithiation rate can be reached (95.83 %). Furthermore, Cu2+ can be regenerated by bubbling O2 under an acidic atmosphere, which enables the re-utilization of the cathodic solution. The targeted electro-redox system can reduce 2980.49 J of the energy consumption compared with the current electrochemical delithiation method, meanwhile, the utilization of cheaper counter electrode makes it economically viable.

Direct and Rapid High‐Temperature Upcycling of Degraded Graphite

AbstractRecycling the degraded graphite is becoming increasingly important, which can helped conserve natural resources, reduce waste, and provide economic and environmental benefits. However, current regeneration methods usually suffer from the use of harmful chemicals, high energy and time consumption, and poor scalability. Herein, we report a continuously high‐temperature heating (≈2000 K) process to directly and rapidly upcycle degraded graphite containing impurities. A sloped carbon heater is designed to provide the continuous heating source, which enables robust control over the temperature profile, eliminating thermal barrier for heat transfer compared to conventional furnace heating. The upcycling process can be completed within 0.1 s when the degraded graphite rolls down the sloped heater, allowing us to produce the upcycled graphite on a large scale. High‐temperature heating removes impurities and enhances the graphitization degree and (002) interlayer spacing, making the upcycled graphite more suitable for lithium intercalation and deintercalation. The assembled upcycled graphite||Li cell displays a high reversible capacity of ≈320 mAh g−1 at 1 C with a capacity retention of 96% after 500 cycles, comparable to current state‐of‐the‐art recycled graphite. The method is a chemical‐free, rapid, and scalable way to upcycle degraded graphite, and is adaptable to recycle other electrode materials.

Origin of high stability, enhanced specific capacity, and low Li diffusion energy in boron doped Li3V2(PO4)3

Li3V2(PO4)3 (LVP) is a well-known cathode material of Li-ion batteries, whereas the specific capacity is limited by the maximum Lithium (Li) de-intercalation probability associated with vacancy energy. The reason behind this limitation is not known yet, which needs to be address, and the modification needs to be done in the electronic structure to get a more specific capacity. In this work, using First-principles calculation, we have found that Li1 (the tetrahedra geometry) is having a higher Li vacancy energy as compared to Li2 and Li3, which limits the Li de-intercalation below x = 1.8, (where x is Li concentration). The change in bandgap of LVP structure after boron (B) substitution is directly correlated to the change in the oxygen (O) occupancy due to B substitution. As of comparing formation energy plot of pristine LVP and B substituted LVBP structure, we have found that in case of LVBP structure formation of x > 2 Li de-intercalation is possible, which help to enhance the specific capacity up to 205 mAh/g. Overall, we identify the cause of the less specific capacity of LVP and provide the solution by suggestion B doping, which also provides less Li diffusion barrier energy.

Silicon is Embedded in Graphene Layers Through High-Energy Ball Milling as the Anode Material for Lithium-Ion Batteries

Using micron silicon as raw material and multi-layer graphene as carbon source, a sandwich-type silicon-carbon composite material is prepared by high-energy ball milling, in which micro-silicon particles are uniformly embedded between the layers of multi-layer graphene. In the process of lithium deintercalation, the graphene sheet can effectively suppress the volume expansion of silicon, thereby improving the high cycle performance and electronic conductivity of the negative electrode of lithium ion batteries. The results show that the average discharge specific capacities are 3094.8, 2406.1, 1845.2, 1210.1, 657.3mAh/g at current densities of 200, 400, 800, 2000, and 4000mAh/g. Each current density is cycled for 5 cycles. When returning from high current to low current, the capacity can still remain at 1729.4 mAh/g, which is greatly improved compared to 671.4 mAh/g of pure silicon. important meaning. It is of great significance for the application of high-capacity silicon carbon anodes.

Basic Characterization and Sputtering Processing of Diatom‐Based Anode Materials

AbstractSilicon‐based anode materials are advantageous because of its high specific capacity, rich resources and appropriate lithium deintercalation potential. However, it is also limited by some disadvantages including large volume expension, poor electronic conductivity and low Initial Coulomb Efficiency(ICE). Benefitting from the original hierarchical porous structure of diatom and amorphous framework of SiO2, we explore the diatoms cultured on a large scale as the anode materials of lithium batteries. Herein, we obtain a suitable diatom‐based anode material with particle diameter D50 4.065 μm, BET specific surface area 228.28 m2/g and biomass of carbon approximately 25 %, while it successfully solves the problems of volume expansion and electronic conductivity. Furthermore, after facile sputtering processing, we successfully introduced metallic elements into the diatom‐based anode. The elements include 3.40 % of Al, 0.75 % of Ti, 10.40 % of Ni, etc. The charge‐dischare results show that the introduction of both Al and Ti lead to performance improvement in some extend.

SiO-induced thermal instability and interplay between graphite and SiO in graphite/SiO composite anode

Silicon monoxide (SiO), which exhibits better cyclability compared to silicon while delivering higher capacity than that of graphite, is an adequate material for the development of lithium-ion batteries (LIBs) having higher energy densities. However, incorporating silicon-based materials including SiO into stable graphite anode inevitably degrades not only cycle life but also calendar life of LIBs, while little is known about their aging mechanisms. Here, SiO-induced thermal instability of the graphite/SiO composite anode is investigated. We reveal that under thermal exposure, SiO accelerates the loss of lithium inventory and concomitantly facilitates the lithium de-intercalation from graphite. This self-discharge phenomenon, which is weakly observed in the graphite anode without SiO, is the result of preferential parasitic reaction on the SiO interface and spontaneous electron and lithium-ion migration to equilibrate the electron energy imbalance between graphite and SiO. Understanding this underlying electron-level interplay between graphite and SiO in the composite anode will contribute toward improving shelf life of SiO-containing LIBs in actual operating conditions.

Electronic structure of LiAl3Bx compound. Effect of boron on lithium deintercalation

Electronic structure of LiAl3Bx compound. Effect of boron on lithium deintercalation

Island-like CeO2 decorated LiMn2O4: Surface modification enhancing electrochemical lithium extraction and cycle performance

Extracting lithium from salt lakes is an effective way to relieve the shortage of lithium resources. Electrochemical lithium extraction has attracted wide attention due to its high selectivity, eco-friendliness, and high-efficiency. Functional surface coating is an effective approach to improve the cycling performance, stability, and conductivity of the electroactive materials. In this work, LiMn2O4 (LMO) electrode materials were prepared via sol–gel method with island-like CeO2 coating (CeLMO) for lithium electrochemical adsorption from simulated brine. CeO2 is helpful to inhibit the agglomeration of active metal oxides and promote the contact and electron transfer between metal oxides. Based on the results from X-ray diffraction, X-ray photoelectron, and Raman spectroscopy, the fate of lithium intercalation and deintercalation in CeLMO is illuminated. CeLMO-2//Ag electrochemical system can produce 96% pure Li+ from Li2CO3 precipitated mother liquor, and the adsorption capacity is 36.52 mg·g−1. The capacity retention after 30 cycles was 60% at 50 mA·g−1, and the Mn dissolution loss rate is 0.016%. In summary, island-like oxide coating improves electrochemical lithium adsorption efficiency and is a promising technology for producing battery-grade lithium products.

Toward the efficient direct regeneration of spent cathode materials through the effect of residual sodium ions analysis

Recycling spent lithium-ion batteries is an important means for promoting sustainability within the energy industry. In this study, the effects of residual sodium on the regeneration process and the performance of spent LiNi0.5Co0.2Mn0.3O2 were explored. An appropriate amount of residual sodium was found to improve the properties of the regenerated material, with the best cycle performance and rate performance at a residual sodium of 3 mol %. The first-cycle and 100-cycle discharge capacities were 136.4 mA h g−1 and 120 mA h g−1, respectively, with a capacity retention rate of 87.98% after 100 cycles at a rate of 1 C. The electrochemical performance of the regenerated cathode materials was improved because sodium occupied the lithium sites in the crystal structure, providing a channel for lithium deintercalation. These results indicate that the residual sodium ions should be monitored in appropriate quantities to improve the efficiency of recycling spent lithium-ion batteries.

Engineering Ag nanoparticles and amorphous MoOx on three dimensional N-doped carbon networks for enhanced lithium storage performance

Molybdenum-based oxides have been widely investigated as promising material for lithium ion batteries owing to their unique physical and chemical properties as well as the large specific capacities. However, the fast capacity fading and poor cyclability originated from the large volume expansion and the sluggish electrode kinetics still inhibit their practical application. Herein, Ag nanoparticles combined with amorphous MoOx-in-plane nanoconfined on three dimensional N-doped porous carbon networks (3DNC) are designed and synthesized through salt-template strategy accompanied by annealing treatment and hydrothermal method (3DNC-MoOx-Ag). The synergistic effect of Ag nanoparticles and amorphous MoOx can inhibit the “dead volume” and aggregation of the electrode, accommodate the volume change, accelerate the diffusion kinetics during the lithium ion intercalation and de-intercalation processes. As a result, the designed 3DNC-MoOx-Ag delivers prominent cycling stability (834 mAh g−1 after 100 cycles at 200 mA g−1) and excellent rate performance (419 mAh g−1 after 70 cycles at 5000 mA g−1). Even at 5000 mA g−1, a specific capacity as high as 369 mAh g−1 can be achieved after 500 cycles.

Volume Change Behavior of Graphite Electrode for Lithium-Ion Battery By in Situ Electrochemical Dilatometry

Graphite undergoes volume expansion and contraction upon lithium ion intercalation and deintercalation process, which affect the internal microstructure of graphite electrode during cycling. In this work, the expansion and contraction in graphite electrode was investigated using in situ electrochemical dilatometry to determine which factor affect the volume change behavior. It was found that the thickness change of the graphite electrode was highly correlated with the microstructure of graphite electrode, such as the preferential orientation of graphite particles, pore structure of graphite electrodes. It was also found that the differential expansion plots of graphite electrodes provides more detailed information on the expansion and contraction behavior of Li ions inserted into graphite. Detailed findings obtained from in situ dilatometry on the graphite electrode will be discussed in the presenation.

Atomic-Scale Investigation of the Reversible α- to ω-Phase Lithium Ion Charge – Discharge Characteristics of Electrodeposited Vanadium Pentoxide Nanobelts

Using an electrochemical potential pulse methodology in a mixed solvent system, electrochemical deposition of amorphous vanadium pentoxide (V2O5) nanobelts is possible. Crystallisation of the material is achieved using in air annealing with the temperature of crystallisation identified using in-situ heating transmission electron microscopy (TEM). The resulting α-phase V2O5 nanobelts have typical thicknesses of 10-20 nm, widths and lengths in the range 5-37 nm (mean 9 nm) and 15 - 221 nm (mean 134 nm), respectively. One-cycle reversibility studies for lithium intercalation (discharge) and de-intercalation (charge) reveal a maximum specific capacity associated with three lithium ions incorporated per unit cell, indicative of ω-Li3V2O5 formation. Aberration corrected scanning TEM confirm the formation of ω-Li3V2O5 across the entirety of a nanobelt during discharge and also the reversible formation of the α-V2O5 phase upon full charge. Preliminary second cycle studies reveal reformation of the ω-Li3V2O5, accompanied with a morphological change in the nanobelt dimensions. Achieving α-V2O5 to ω-Li3V2O5 to α-V2O5 reversibility is extremely challenging given the large structural rearrangements required. This phenomenon has only been seen before in a very limited number of studies, mostly employing nanosized V2O5 materials and never before with electrodeposited material. Figure 1