Pre-lithiation Process Research Articles

Roll-to-roll Prelithiation of Li-ion Batteries Anodes Using Ultrathin Lithium Strips

The irreversible formation of solid electrolyte interphase (SEI) reduces lithium-ion batteries’ capacity and energy density (LIBs), prompting the prelithiation strategies to compensate for the Li loss. However, the accuracy of the prelithiation degree and the SEI formation under prelithiation conditions remain key issues, especially for practical industrial production. Herein, we demonstrate that roll-to-roll prelithiation of graphite anodes can be done using ultrathin lithium strips (6-μm-thick), and the prelithiation degree can be precisely tuned by the topological distribution. More importantly, the formation of SEI during the prelithiation process and its influence on the long-term cycling performance of the prelithiated LiFePO4 || graphite pouch cells was revealed. Afterward, the prelithiated pouch LiFePO4 || graphite cell at the optimized conditions exhibits the upgraded energy density after even 1200 cycles. This study shall provide an industrial-scale prelithiation technique for high-energy–density LIBs and a pioneering systematic investigation of SEI chemistry during prelithiation.

Molecular Engineering Chemical Pre-lithiation Reagent with Low Redox Potential for Graphite Anode Enables High Coulombic Efficiency.

Graphite (Gr) is a low-cost and high-stability anode for lithium-ion batteries (LIBs). However, Gr anode exhibits an obstinate drawback of low initial Coulombic efficiency (ICE), owing to the active lithium loss for the solid electrolyte interphase (SEI) layer. Herein, a straightforward and effective chemical pre-lithiation strategy is proposed to compensate for the lithium loss. A molecular engineering phenanthrene-based lithium-arene complex (Ph-based LAC) reagent is designed by density functional theory (DFT) calculations. The engineering Ph-based reagent enhances the stability of the π-electron system and the electron-donating capacity, resulting in a reduced redox potential to facilitate lithium transfer. The electrochemical distinct of the Ph-based reagent is illustrated, the prelithiation process in a low Li-insertion platform, and the lithiation degree is controllable with the dipping time (ICE = 102%, 3min). Notably, a denser and homogeneous SEI layer has pre-formed to enhance the Li+ transport and interface stability. Moreover, the lithium-ion full batteries assemble with LiFePO4 and NCM811 cathode, which exhibits high ICE (96.5% and 90.3%) and energy density (310 and 333Whkg-1). These findings present a facile and controllable pre-lithiation strategy to compensate for the lithium of LIBs, providing new valuable insights into the design and optimization of battery manufacture.

A high-efficiency pre-lithiation strategy for Li-ion capacitor achieved by the synergistic effect of pre-lithiation and solid electrolyte interface film modification

The cathodic pre-lithiation process, currently considered the most feasible resolution to address the irreversible depletion of Li+ in dual carbon-based lithium-ion capacitors (LICs), encounters obstacles in widespread adoption due to its substantial dosage requirement, rising decomposition potential and the damage related to its decomposition residues. Hence, in this study, the successful utilization of Li2NiO2 for LIC pre-lithiation is accomplished, leveraging the synergistic effect between Li2NiO2 and lithium difluoro oxalate borate (LiDFOB). It's noteworthy that the full capacitor, entirely composed of commercial materials (activated carbon/hard carbon) and supplemented with 20 wt% LNO +2 wt% LiDFOB, exhibits remarkable energy densities of 98.53 Wh kg−1 at a power density of 31 W kg−1 and 19 Wh kg−1 at a power density of 4.65 kW kg−1. Moreover, the full capacitor displays commendable performance, demonstrating superior capacitive behavior and excellent high-current cycling proficiency. Besides, electrochemical evaluations and structural analyses unveil that LiDFOB, via solid electrolyte interface (SEI) modification, enhances the utilization of Li+ sourced from Li2NiO2 thus avoiding the abuse of pre-lithiation reagents, while the LNO decomposition products contribute substantially to additional capacitance. The synergistic effect of pre-lithiation reagent and SEI modification underpin the outstanding performance witnessed in the full capacitor.

Prelithiated Silicon Anodes for High-Energy and High-Power Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are pivotal in powering modern electronic devices and next-generation land and air electric vehicles. Silicon-based anodes are considered the next technology to replace traditional graphite anodes due to their high theoretical capacity. However, the inherent challenges associated with their large volume expansion and high irreversible capacity loss (IRCL) limit their practical application. This abstract explores our patented strategy of prelithiation as a viable approach to mitigate the IRCL limitations of SiOx dominant anodes. Prelithiation involves the precise addition of supplemental lithium into the anode, mitigating the adverse effects of initial lithiation and enhancing overall cyclability, energy, power, and extreme fast charge capability for silicon oxide dominant LIBs. Various prelithiation techniques, including Li powder, Li slurry, Li-foil, and the chemical doping of SiOx are examined to evaluate their effectiveness in providing supplemental lithium. The effectiveness of the prelithiation process is assessed by examining the impact on the structural stability, cycling performance, power capability, and rate capability of SiOx dominant anodes integrated into high-capacity (~30 Ah) pouch cells. Our focus is to emphasize prelithiation as a practical and scalable solution to enhance the electrochemical performance of SiOx dominant anodes, contributing to the development of high-energy and high-power LIBs enabling advanced air mobility and high-performance electric vehicles. The findings presented in this abstract contribute to the growing body of knowledge aimed at advancing the fundamental understanding and practical implementation of prelithiation as an enabler for SiOx-based anodes in LIBs. Figure 1

Favored Amorphous LixSi Process with Restrained Volume Change Enabling Long Cycling Quasi-Solid-State SiOx anode.

Silicon-based anodes are becoming promising materials due to their high specific capacity. However, the intrinsically large volume change brought about by the alloying reaction results in the crushing of the active particles and destruction of the electrode structure, which severely limits its practical application. Various structured and modified silica-based anodes exhibit improved cycling stability and the demonstrated ability to mitigate their volume changes through interfacial and binder strategies. However, the issue of large volume changes in silicon-based anodes remains. Herein, we report a gel polymer electrolyte (GPE) prepared through an in situ thermal polymerization process that is suitable for SiOx anode materials and achieving long-term cycling stability. GPE-based cells essentially mitigate the volume change of SiOx anodes by guiding the unique lithiation/delithiation mechanism that tends to favor the formation and delithiation of amorphous-LixSi (a-LixSi) with smaller volume change, thereby mitigating electrode damage and cracking, and achieving the significant improvement in cycling performance. The prepared GPE-SiOx cells retained 693.80 mAh g-1 reversible capacity after 450 cycles at 500 mA g-1. In addition, the prelithiation process was incorporated to mitigate capacity fluctuations and improve the Initial Coulombic Efficiency (ICE), and a reversible capacity of 641.90 mAh g-1 was retained after 480 cycles.

In Situ Construction of Specific SEI Layer Affords Effective Prelithiation.

Silicon-based anodes have been attracting attention due to their high theoretical specific capacity, but their low initial Coulombic efficiency (ICE) seriously hinders their commercial application. Direct contact prelithiation is considered to be one of the effective means of solving this problem. By means of prelithiation, a specific solid electrolyte interphase (SEI) was constructed, which inhibited the volume expansion of the SiO/C composite anode during prelithiation and reduced the local current generated when the lithium source was in contact with the anode. On the one hand, it can reduce the side reactions derived from the decomposition of electrolytes in the prelithiation process, and on the other hand, it can slow down the prelithiation process and inhibit the volume expansion of the SiO/C composite anode in the prelithiation process. The results of XPS, TOF-SIMS, and other tests show that the use of an electrolyte whose main component is LiTFSI can construct SEI film whose main component is LiF, which to a certain extent can slow down the rate of prelithiation, reduce the local current generated when the lithium source is in contact with the negative electrode, minimize the occurrence of side reactions, and inhibit the volume expansion of the negative electrode material. The full battery assembled with NCM111 positive electrode still exhibits 83.5% capacity retention after 500 cycles at 1 C current density. These studies provide some ideas to enhance the performance of silicon-based materials.

Mechanistic insight into the impact of dry-state prelithiated SiOx thin-film anode toward extremely fast-charging and long-term stability

Silicon suboxides (SiOx) have achieved partial success in commercialization as high-capacity anode materials to replace graphite because of optimal electrochemical properties over silicon. Unfortunately, the further development has been sluggish, jeopardizing the urgent need of green energy. The daunting challenges to tackle include low initial coulombic efficiency (ICE) and low charging rate due to poor electron and ionic conductivity. In the context of thin film microbattery, we propose to precisely control the chemical states of SiOx films through varying sputtering power followed by dry-state pre-lithiation through Li-metal thermal evaporation, superior to the current pre-lithiation approaches for SiOx thin-film anodes. We addressed the leading roles of the surface chemical states of the as-deposited SiOx in the formation of the high ionic conductive Li4SiO4 phase as the pre-solid electrolyte interphase during the proposed dry-state prelithiation process. Ultimately, the prelithiated SiOx successfully mitigated the most confronted issues as low ICE and C-rate limitation, achieving an unprecedented rate performance of 72.8 % at 20 C, and ultra-long-cycle retention of 54.2 % over 5000 cycles at 10 C. These results strongly prove that appropriate pre-lithiation provides tremendous advantages to SiOx thin film anode not only in prolonging electrode stability but also promoting a significant fast-cycling.

Dual-Carbon Phase-Encapsulated Prelithiated SiOx Microrod Anode for Lithium-Ion Batteries.

Among silicon-based anode family for Li-ion battery technology, SiOx, a nonstoichiometric silicon suboxide holds the potential for significant near-term commercial impact. In this context, this study mainly focuses on demonstrating an innovative SiOx@C anode design that adopts a pre-lithiation strategy based on in situ pyrolysis of Li-salt of silsesquioxane trisilanolate without the need for lithium metal or active lithium compounds and creates dual carbon encapsulation of SiOC nanodomains by simply one-step thermal treatment. This ingenious design ensures the pre-lithiation process and pre-lithiation material with high-environmental stability. Moreover, phenyl-rich organosiloxane clusters and polyacrylonitrile polymers are expected to serve as internal and external carbon source, respectively. The formation of an interpenetrating and continuous carbon matrix network would not only synergistically offer an improved electrochemical accessibility of active sites but also alleviate the volume expansion effect during cycling. As a result, this new type of anode delivered a high reversible capacity, remarkable cycle stability as well as excellent high-rate capability. In particular, the L2-SiOx@C material has a high initial coulomb efficiencof 80.4% and, after 500 cycles, a capacity retention as high as 97.5% at 0.5 A g-1 with a reversible specific capacity of 654.5mA h g-1.

Facile Synthesis and Electrochemical Analysis of Zn-Doped V2O5 Anode Materials for High-Rate Li Storage

The surging demand for Li rechargeable batteries with high energy densities and rapid rate capability has propelled research on materials that can replace the conventional anode materials like graphite. Vanadium pentoxides (V2O5) have emerged as promising anode candidates owing to their excellent rate capability. Specifically, V2O5 allows the electrochemical prelithiation process, in which three Li-ions can be inserted to form Li3V2O5, followed by reversible insertion and extraction of two Li-ions. Nevertheless, the unsatisfactory Li-ion diffusion coefficients and electrical conductivities of these materials remain major drawbacks. Here, we propose a Zn-doped V2O5 anode, fabricated using a two-step sol–gel method, for high-rate Li-ion batteries. Zn was incorporated into V2O5 to enhance the Li-ion transport kinetics through the electrode. The crystal structure (orthorhombic) of Zn-doped V2O5 was identified by X-ray diffraction analysis, and the Zn doping was confirmed by X-ray photoelectron microscopy. The effect of Zn doping was thoroughly examined using various analytical methods, such as cyclic voltammetry and galvanostatic intermittent titration technique. The Zn-doped V2O5 electrode exhibited remarkable cycling durability, enduring for 1000 cycles, while retaining an enhanced capacity, even under a high rate of 2C.

Facilitating prelithiation of silicon carbon anode by localized high‐concentration electrolyte for high‐rate and long‐cycle lithium storage

AbstractThe commercialization of silicon‐based anodes is affected by their low initial Coulombic efficiency (ICE) and capacity decay, which are attributed to the formation of an unstable solid electrolyte interface (SEI) layer. Herein, a feasible and cost‐effective prelithiation method under a localized high‐concentration electrolyte system (LHCE) for the silicon–silica/graphite (Si–SiO2/C@G) anode is designed for stabilizing the SEI layer and enhancing the ICE. The thin SiO2/C layers with –NH2 groups covered on nano‐Si surfaces are demonstrated to be beneficial to the prelithiation process by density functional theory calculations and electrochemical performance. The SEI formed under LHCE is proven to be rich in ionic conductivity, inorganic substances, and flexible organic products. Thus, faster Li+ transportation across the SEI further enhances the prelithiation effect and the rate performance of Si–SiO2/C@G anodes. LHCE also leads to uniform decomposition and high stability of the SEI with abundant organic components. As a result, the prepared anode shows a high reversible specific capacity of 937.5 mAh g−1 after 400 cycles at a current density of 1 C. NCM 811‖Li‐SSG‐LHCE full cell achieves a high‐capacity retention of 126.15 mAh g−1 at 1 C over 750 cycles with 84.82% ICE, indicating the great value of this strategy for Si‐based anodes in large‐scale applications.

Experimental Considerations of the Chemical Prelithiation Process via Lithium Arene Complex Solutions on the Example of Si‐Based Anodes for Lithium‐Ion Batteries

Experimental Considerations of the Chemical Prelithiation Process via Lithium Arene Complex Solutions on the Example of Si‐Based Anodes for Lithium‐Ion Batteries

Experimental Investigation of the Lithium Calendering Process for Direct Contact Prelithiation of Lithium‐Ion Batteries

Lithium‐ion batteries suffer from high initial capacity losses during formation. One possible approach to compensate for these initial capacity losses is prelithiation, which is the addition of lithium into the battery cell before formation. A promising method is direct contact prelithiation using lithium foil, which requires lithium foil thicknesses below 10 μm to ensure the safe and accurate performance of the prelithiation process. However, free‐standing lithium foils are only commercially available down to a thickness of 20 μm; hence, in this present work, the calendering process of lithium is investigated in detail. An already developed process model will be adapted to provide detailed information on the deformation properties and thickness reduction of different lithium foil thicknesses. A design of experiments is used to investigate the influences of lithium foil geometry, line load, web speed, and roller temperature on the deformation behavior of lithium during calendering. Lithium foil is applied onto anodes by calendering, which are electrochemically investigated using pouch cells. The cells prelithiated by calendering show improved electrochemical performance compared to the manually prelithiated cells, increasing cycle life by 19%.

Experimental Considerations of the Chemical Prelithiation Process via Lithium Arene Complex Solutions on the Example of Si‐Based Anodes for Lithium‐Ion Batteries

Losses of Li inventory in lithium‐ion batteries lead to losses in capacity and can be compensated by electrode prelithiation before cell assembly or before cell formation. The approach of chemical prelithiation, for example, via Li arene complex (LAC)‐based solutions is technically an apparently simple and promising approach. Nevertheless, as shown herein on the example of Si‐based anodes and LAC solutions based on 4,4′‐dimethylbiphenyl (4,4′‐DMBP), several practical challenges need to be considered. Given their reactivity, the LAC solution can not only decompose itself within a range of a few hours, as seen by discoloration and confirmed via mass spectrometry, but can also decompose its solvent and binder of added composite electrodes. Effective prelithiation requires an excess in capacity of the LAC solution (relative to anode capacity) and optimized system characteristic conditions (time, temperature, etc.) as exemplarily shown by comparing Si‐based nanoparticles with nanowires. It is worth noting that the prelithiation degree alone does not determine the boost in cycle life, but relevantly depends on previously applied prelithiation conditions (e.g., temperature), as well.

Effect of Electrochemical Pre-Lithiation on Layered Oxide Cathodes for Anode-Free Lithium-metal Batteries.

Due to high energy density and lower manufacturing cost, anode-free lithium-metal batteries (AFLMBs) are attracting increasing attention. The challenges for developing them lie in inferior Coulombic efficiency and short cycle life due to the highly reactive lithium metal. Herein, an electrochemical pre-lithiation strategy is applied to layered oxide cathodes, specifically LiNiO2 and LiCoO2 , aiming to provide an additional lithium source and understand the effect on the cathode structure for AFLMBs. The mechanism for accommodating the excess Li depends on the structural stability of the cathodes where LiNiO2 forms lithiated Li2 NiO2 with the excess lithium in the crystalline lattice while the excess lithium in LiCoO2 forms a Li2 O phase. More importantly, an optimal amount of Li excess is necessary to maintain decent cycle stability and specific capacity in AFLMB, with 40% excess Li for LiNiO2 and 150% for LiCoO2 . While the pre-lithiation process causes particle pulverization depending on the amount of Li excess, LiCoO2 offers a much better cycle performance than LiNiO2 with a promising capacity retention of 80% after 300 cycles in AFLMB (vs 76% after 100 cycles for 40% Li excess in LiNiO2 ). This study provides a promising avenue for developing tailor-made layered oxide cathodes for AFLMBs.

Improving the electrochemical performance of lithium‐ion battery using silica/carbon anode through prelithiation techniques

AbstractThis work focuses on the two most common techniques, including the direct contact method (CM) and the electrochemical method (EM) in the half‐cell applied for the SiO2/C anode. After the prelithiation process, the anodes would be assembled in the coin cells paired with NMC622 cathode. According to electrochemical performance, prelithiation techniques could strengthen the initial discharged capacity and Coulombic efficiency. While the nonprelithiated sample exhibits a poor discharged capacity of 48.43 mAh·g−1 and low Coulombic efficiency of 87.41% in the first cycle, the CM and EM methods illustrated a better battery performance. Specifically, the EM4C exhibited a higher initial discharged capacity and Coulombic efficiency (137.06 mAh·g−1 and 95.82%, respectively) compared to the CM30 (99.08 mAh·g−1 and 93.23%, respectively). As a result, this research hopes to bring some remarkable information to improve full‐cell properties using SiO2/C as an anode material by the prelithiation method.

Tailored Pre-Lithiation of Carbon Anodes Using Melt Deposited Thin Lithium

The user demands for Lithium ion batteries in mobile applications and electric vehicles request steady improvement in terms of capacity and cycle life. State-of-the-art lithium ion batteries irreversibly loose about 10 % of the capacity during the first cycles due to SEI formation. Therefore, 10 % of the cathode material is not used during the rest of the cells life which results in a waste of cathode material and leads to a lowered range of battery electric vehicles. Therefore, these losses must be compensated to ensure efficient resource utilization and to further increase the capacity of the lithium ion battery.We have developed a method to compensate these capacity losses by pre-lithiation: A fast and simple approach of electrolyte-free direct contact pre-lithiation leads to targeted degrees of pre-lithiation in a range of 7-50 % for state-of-the-art graphite electrodes. The parameters pressure (0-40 MPa), temperature (20-150°C) and time (0-60 min) are used to transfer lithium from a temporary substrate to the graphite anode. This process uses 1-5 µm thin lithium films made by the Fraunhofer IWS lithium melt deposition process as a lithium source.[1] The degree of pre-lithiation can be controlled by the lithium loading of the temporary substrate. NCM full cells built with pre-lithiated graphite electrodes where electrochemically evaluated in comparison to unlithiated electrodes. They show 6.5 % capacity increase after the first cycles using the additional lithium to form the SEI during the first cycles. The parameter influence of the pre-lithiation process on the initial coulomb efficiency of cells with pre-lithiated graphite electrodes is examined in half cells showing an ICE of 99.91 % for the best parameters.This method of electrolyte-free direct contact pre-lithiation shows an efficient way to further increase the capacity of state-of-the-art LIBs with graphite electrodes by increasing the cathode material utilization. It can potentially be scaled up to a roll-to-roll process using a heated calender nip. The temporary substrates with tailored lithium loading can be processed by lithium melt deposition in an efficient way with high lithium yield and high precision.[1] K. Schönherr, B. Schumm, F. Hippauf, R. Lissy, H. Althues, C. Leyens, S. Kaskel, Chemical Engineering Journal Advances 2022, 9, 100218. Figure 1

New Class of High-Energy, High-Power Capacitive Devices Enabled by Stabilized Lithium Metal Anodes.

Lithium-ion capacitors (LIC) combine the energy storage mechanisms of lithium-ion batteries and electric double layer capacitors (EDLC) and are supposed to promise the best of both worlds: high energy and power density combined with a long life. However, the lack of lithium cation sources in the carbon cathode demands the cumbersome step of prelithiation of the graphite anode, mainly by using sacrificial lithium metal, hindering the mass adoption of LICs. Here, in a conceptually new class of devices termed lithium metal capacitors (LMC), we replace the graphite anode with a lithium metal anode stabilized by a complex yet stable solid-electrolyte interface (SEI). Via a specialized formation process, the well-explored synergetic reaction between the LiNO3 additive and controlled amounts of polysulfides in an ether-based electrolyte stabilizes the SEI on the lithium metal electrode. Optimized devices at the coin cell level deliver 55 mAh g-1 at a fast 30C discharge rate and maintain 95% capacity after 8000 cycles. At the pouch-cell level, energy densities of 13 Wh kg-1 are readily achieved, indicating the transferability of the technology to practical scales. The LMC, a new class of capacitive device, eliminates the prelithiation process of the conventional LIC, allowing practical production at scale and offering exciting avenues for exploring versatile cathode chemistries on account of using a lithium metal anode.

High performance Li-ion battery-type hybrid supercapacitor devices using antimony based composite anode and Ketjen black carbon cathode

We report on antimony (Sb) and silicon (Si) based microstructured composite based lithiated anodes and their performance in battery-type hybrid supercapacitor devices. Ketjen-black carbon - 600 (or C-600) was used as capacitor-type cathode. For synthesis of materials, we employed a two-step process, viz., high probe sonication of the precursor materials followed by annealing at 700 °C for 1 h. The materials, namely, pure bulk Sb; Sb@C and Sb@Si/C were analyzed for phase, surface microstructure, and chemical states using X-ray diffraction (XRD), field emission scanning electron microscopy (FE SEM)/energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. The as-synthesized alloy composites were pre-lithiated employing Li-ion battery (LIB) half-cell system via electrochemical pre-lithiation process in a fixed voltage range of 0.01–1.5 V for 8–10 charge-discharge cycles. Additionally, LISC devices, consisting of lithiated alloy-based anodes, and fresh C-600 carbon cathode, were successfully tested by electrochemical measurements, viz., Cyclic voltammetry (CV) electrochemical impedance spectroscopy (EIS) galvanostatic charge/discharge (GCD) techniques. The full-cell hybrid LISC devices were characterized at 1.5–4.0 V. The specific capacitances calculated for Sb//C-600, Sb@C//C-600, and Sb@Si/C//C-600 are 81.07 F/g, 153.96 F/g and 188.27 F/g, respectively, at a current density of 3 mA/g. The Sb@Si/C//C-600 LICS device delivered a maximum specific energy density of 163.42 Wh/kg, capacitive retention of 68.95 % for consecutive 10,000 cycles at 10 mA/g and an excellent cyclic stability conducive for the development of energy storage devices.

Tailored Pre-Lithiation Using Melt-Deposited Lithium Thin Films

The user demands lithium-ion batteries in mobile applications, and electric vehicles request steady improvement in terms of capacity and cycle life. This study shows one way to compensate for capacity losses due to SEI formation during the first cycles. A fast and simple approach of electrolyte-free direct-contact pre-lithiation leads to targeted degrees of pre-lithiation for graphite electrodes. It uses tailor-made lithium thin films with 1–5 µm lithium films produced by lithium melt deposition as a lithium source. These pre-lithiated graphite electrodes show 6.5% capacity increase after the first cycles in NCM full cells. In this study, the influence of the pre-lithiation parameters—applied pressure, temperature and pressing time—on the pre-lithiation process is examined.

Controlled prelithiation of siloxene nanosheet anodes enables high performance 5 V-class lithium-ion batteries

Two-dimensional siloxene nanosheet has attracted great attention as an advanced anode for lithium-ion batteries (LIBs) due to its special characters. However, the high surface area leads to a low initial Coulombic efficiency (ICE) and large irreversible capacity, impeding the further application of siloxene. In this work, controlled chemical prelithiation is designed to overcome the issue. The influences of prelithiated conditions on physical and electrochemical performance are researched. Uniform SEI film and high coulombic efficiency is obtained with a 15 min prelithiation process. The prelithiated siloxene anode shows high ICE, superior rate performance and stable cycling performance. When coupled with 5 V-class LiNi0.5Mn1.5O4 cathodes, an enhanced capacity retention of 94.3 % is achieved after 200 cycles. This work may be useful for designing advanced anodes for rechargeable batteries.