Active Lithium Research Articles

Degradation identification of LiNi0.8Co0.1Mn0.1O2/graphite lithium-ion batteries under fast charging conditions

Cycle aging of commercial 2.5 Ah 18650 cylindrical lithium-ion batteries with LiNi0.8Co0.1Mn0.1O2(NCM)/graphite chemistry is investigated at different charging rates. The cells charged at 1C-3C follow a similar aging path, and the degradation mechanisms under 2C and 3C charging are characterized by non-destructive electrochemical techniques and post-mortem analyses. Electrochemical impedance spectroscopy measurements indicate that the impedance rise of cells is primarily attributed to the increase of charge transfer resistance. Post mortem analyses reveal that the side reactions on NCM cathode are secondary particle cracking and transition metal dissolution, and anode degradation is caused by the growth of solid-electrolyte interface layer and the lithium plating. Voltage fitting analyses of 3C charging demonstrate that the main degradation mode is the insufficient active lithium that is available for intercalation/deintercalation in highly-lithiated anodes. Quantitative analyses of the individual electrodes based on differential voltage curves identify that loss of lithium inventory (LLI) contributes the dominant aging mode to full cell, followed by loss of active material of delithiated negative electrode (LAMdeNE) and LAM of lithiated negative electrode (LAMliNE), while LAM of positive electrode (LAMPE) exerts a minor effect. Accurate identification of the battery degradation mechanisms cycling under fast charging conditions helps to provide guidance for charging optimization.

Revealing the Failure Mechanism of Partially Lithiated Silicon-Dominant Anodes Based on Microscale Silicon Particles

Due to its high capacity, rate capability and attractive cost position, the partial lithiation of silicon microparticles in anodes for Lithium Ion Batteries (LIB) is a material concept worth considering. Limitations in cycling stability and volume change currently limit its deployment to niche applications with moderate cycle life requirements and thus prevent a broader market introduction. The present study discusses the failure mechanism of LIB cells based on partially lithiated silicon dominant anodes. The loss of active lithium is reflected in a comparatively strong capacity decrease, especially at low cut-off voltages. The developed electrochemical methodology enables to differentiate between various loss contributions, such as lithium loss by electronic particle decoupling or particle isolation, trapping of mobile lithium and immobilization of lithium in the solid electrolyte interphase (SEI). The study identifies the continuous formation of SEI as the main failure mechanism, while particle decoupling, in addition, mainly contributes when operating at low discharge voltages. Approaches to increasing the cell performance consequently lie in the optimization of the electronic particle connection and in the development of improved electrolyte systems and/or pre-lithiation strategies to improve the cycle stability of silicon-based LIB cells.

Evaluation on a 400 Wh kg−1 lithium–sulfur pouch cell

Lithium–sulfur (Li–S) batteries are highly regarded as next-generation energy storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg−1. However, practical high-energy-density Li–S pouch cells suffer from limited cycling lifespan with rapid loss of active materials. Herein, systematic evaluation on a 400 Wh kg−1 Li–S pouch cell is carried out to reveal the working and failure mechanism of Li–S batteries under practical conditions. Electrode morphology, spatial distribution and species analysis of sulfur, and capacity retention of electrodes are respectively evaluated after the first cycle of discharge or charge. Considerable lithium polysulfides are found in electrolyte even at the end of discharge or charge, where the sulfur redox reactions are reversible with high capacity retention. Meanwhile, severe morphology change is identified on lithium metal anode, yet there remains substantial active lithium to support the following cycles. This work not only demonstrates unique behaviors of Li–S batteries under practical conditions, which is essential for promoting the progress of Li–S pouch cells, but also affords a systematic evaluation methodology to guide further investigation on high-energy-density Li–S batteries.

Promises and Challenges of the Practical Implementation of Prelithiation in Lithium‐Ion Batteries

AbstractLithium‐ion batteries (LIBs) have changed lives since their invention in the early 1990s. Further improvement of their energy density is highly desirable to meet the increasing demands of energy storage applications. Active lithium loss in the initial charge process appreciably reduces the capacity and energy density of LIBs due to the formation of a solid electrolyte interface (SEI) on the anode surface, especially for Si based anodes in high‐energy‐density batteries. To solve this issue, prelithiation to provide additional active lithium into the battery has been widely accepted as one of the most promising strategies. Here, key parameters/issues for the practical implementation of prelithiation approaches in LIBs are discussed, including donable lithium‐ion capacity/prelithiation efficiency, chemical and ambient stability of the prelithiation materials/reagents, safety hazards of prelithiation, residues and side reactions during prelithiation, potential effect on electrochemical performance, industrial compatibility, and scalability of the prelithiation, many of which are often overlooked in academic literature. Moreover, insights are offered regarding the potential future directions in the development of this burgeoning field. Continuous progress in prelithiation is essential and urgent to enable next‐generation high‐energy‐density LIBs in the near future.

Organic salts with unsaturated bond and diverse anions as substrates for solid electrolyte interphase on graphite anodes

The electrochemical performance of lithium ion batteries is closely related to the solid electrolyte interphase (SEI) film formed on anode surface. Despite the widespread commercialization of graphite anodes, SEI still suffers from unsatisfactory stability, leading to gradual loss of active lithium ions and capacity degradation of batteries. Here organic small molecular salts with unsaturated bonds and diverse anions are coated on graphite particles and work as substrates to form a modified SEI. The CC double bond-containing organic salts, sodium acrylate (SA), sodium vinylsulfonate (SVS) and vinyl sodium phosphate (VSP), possessing carboxylate, sulfonate and phosphate groups, respectively, are rationally selected and their effects on the SEI and electrochemical properties of graphite anodes are systematically investigated. SVS modified graphite generates a SEI film with high flexibility, good compactness and lithium ions conductivity owning to the in-situ polymerization of carbon double bonds and polarity of ionic sulfonate groups. Accordingly, the first coulombic efficiency, rate capability and cycle life of graphite anodes are improved in both half cell and LiNi0·6Co0·2Mn0·2O2-based full cell testing.

Highly active zinc oxide-supported lithium oxide catalyst for solvent-free Knoevenagel condensation

Highly active zinc oxide-supported lithium oxide catalyst for solvent-free Knoevenagel condensation

Lithium and Electrolyte Distribution in 18650-Type Lithium-Ion Batteries

Extensive cycling of lithium-ion batteries leads to a partial loss of their capacity due to various side effects like formation of the solid-electrolyte-interface (SEI), loss of active lithium, drying out of the cell [1, 2] etc. Typical profiles of side reactions, instantaneous temperature[3] and current density[4] are non-uniform, which leads to a heterogeneous lithium distribution in the battery. The loss of lithium inventory is typically correlated with the formation of SEI during cycling, whereas the quantitative role of the electrolyte in the cell operation and cell fatigue remains not fully understood yet.Primarily, this is related to the fact that quantification of the liquid electrolyte in an electrically and environmentally isolated system such as lithium-ion batteries is not a simple task. Opening the system would inhibit changes of its state, e.g. evaporation of electrolyte. Typical X-ray or neutron-based methods utilized in non-destructive cell characterization are not capable to quantify the amount of liquid electrolyte with desired accuracy. Recently it has been shown that liquid electrolyte (DMC-based) exhibit a long range order, when frozen at T<260 K [5]. This long range order can be detected by neutron diffraction and the amount of frozen electrolyte can be quantified. Furthermore, applying spatially-resolved neutron powder diffraction (Ref. [6]) pave the way for the simultaneous quantification of lithium amount in graphite and relative concentration of frozen electrolyte (Figure 1).The aim of the current study is a non-destructive quantification of lithium and electrolyte, their spatial distribution throughout the cell and concentration changes vs. cell fatigue. Combined experimental studies embedding electrochemistry, X-ray computed tomography, and neutron diffraction is applied for 18650-type cylinder cell based on NCA|C chemistry, where high-resolution neutron diffraction independently reveals a direct correlation between losses of active lithium in the graphite anode and those of liquid electrolyte (both volume-averaged). The 3D lithium distribution is probed by spatially resolved neutron powder diffraction, thereby displaying the non-trivial character of active lithium/electrolyte losses and complex profile of the cell capacity fading.[1] D. Petz, M.J. Mühlbauer, V. Baran, M. Frost, A. Schökel, C. Paulmann, Y. Chen, D. Garcés, A. Senyshyn, Journal of Power Sources 2020, 448, 227466.[2] B. Ziv, V. Borgel, D. Aurbach, J.-H. Kim, X. Xiao, B.R. Powell, Journal of The Electrochemical Society 2014, 161, A1672-A1680.[3] H. Dai, B. Jiang, X. Wei, Energies 2018, 11,[4] S.V. Erhard, P.J. Osswald, P. Keil, E. Höffer, M. Haug, A. Noel, J. Wilhelm, B. Rieger, K. Schmidt, S. Kosch, F.M. Kindermann, F. Spingler, H. Kloust, T. Thoennessen, A. Rheinfeld, A. Jossen, Journal of The Electrochemical Society 2017, 164, A6324-A6333.[5] A. Senyshyn, M.J. Mühlbauer, O. Dolotko, H. Ehrenberg, Journal of Power Sources 2015, 282, 235-240.[6] A. Senyshyn, M.J. Mühlbauer, O. Dolotko, M. Hofmann, H. Ehrenberg, Scientific Reports 2015, 5, 18380. Figure 1

Rechargeable Lithium Metal Pouch Cell Development

Commercially available Li-ion batteries using graphite or graphite-silicon blended anodes are currently approaching a cell level specific energy of 300 Wh kg−1. The use of lithium metal instead as an anode an intriguing possibility to further increase cell level specific energies to 400 Wh kg−1 and beyond. Lithium is an ideal anode because it is the lightest metal and highly electronegative. However, attempts to commercialize cells using lithium metal anodes have been slowed by poor cycle life and safety issues. This is because nonuniform lithium plating leads to the growth of dendrites that cause loss of active lithium and can eventually lead to internal cell shorts. Safe cell cycle life must be improved to 50-100 cycles for special purpose applications like unmanned aerial vehicles, >300 cycles for portable power applications and >1000 cycles for electric vehicle applications.The performance of prototype cells developed at EaglePicher Technologies using lithium metal anode will be highlighted. The figure below on the left shows the specific discharge energy of a 2.5 Ah prototype pouch cell using a lithium anode, high nickel cathode and nonaqueous electrolyte. The cell demonstrates an extremely high specific energy of >400 Wh kg−1 at low rates. The effect of electrolyte on capacity retention is shown in the figure below on the right. The optimized electrolyte demonstrates good retention to >50 cycles. This presentation will focus on design considerations for pouch cells with lithium anodes, as well as improving the cycle life and safety characteristics of these cells. Prototype performance data including cycle life, rate capability, temperature effects and safety testing will be presented.EaglePicher Technologies would like to acknowledge the US Army DEVCOM C5ISR Center in Aberdeen Proving Ground, Maryland for funding this research. Figure 1

Li-Ion Battery Deactivation through External Short Circuit

While electric vehicle battery packs are designed to address safety issues, battery failures can still occur. Most prominently, electric vehicle fires can occur after accidents or from internal shorts due to defects, abuse, or accelerated aging. Battery fires can be difficult to manage due to the active lithium materials and the presence of both the fuel and oxidant produced by thermal decomposition. Typically, after extinguishing the original fire, the main priority is to cool the battery pack by applying a large and continuous volume of water directly to the pack. However, the fire may still reignite hours later, fueled by the remaining stored energy. This highlights the need for further investigation and discussion about how to effectively remove the stored energy from, or deactivate, batteries with the goal to prevent fire re-ignition in battery packs.Batteries at a lower state-of-charge (SOC) are more thermally stable and have a lower energy release during thermal runaway than those at high SOCs. In addition, experimental results from single cells and small, multiple-cell configurations undergoing external short circuits show that thermal runaway (TR) events are rare, and the cell peak temperatures depend on the relative size of the external resistance to the internal cell resistance. To this end, this research aims to evaluate the use of high C-rate discharge and external short circuits to safely deactivate batteries while avoiding TR.External short circuit testing was performed on 4.6Ah pouch cells at 15% and 100% SOC, with measurements of cell current, voltage, temperature, expansion force, and atmospheric CO2 gas concentration. At the end of the test, the cell initially at 15% SOC discharged to -10% SOC and reached a maximum temperature of 64℃. The cell had no visible damage afterwards. For the 100% SOC cell, it reached a maximum temperature of 120℃ and discharged to around 25% SOC at the end. In both cases, neither went into thermal runaway, but the first cell was able to discharge to less than 0% SOC in 5 minutes, while the 100%SOC cell took significantly longer to reach the low current cutoff. This is because during the gas venting process, electrolyte is lost, greatly increasing the internal resistance and increasing the discharge time. In addition, the lower peak temperature of the first cell indicates a reduced likelihood of thermal runaway propagation in a pack, and the lack of toxic and flammable vent gas and electrolyte leakage in the environment improves safety. In order to apply this at a larger level, we will investigate the appropriate external resistance to safely deactivate the cells without leading to hazardous conditions. Figure 1

Real Time Analysis of Dissolution of Active Materials and Current Collectors of Lithium Ion Batteries

In this talk we will address the problem of dissolution of transition metals of cathode active materials (CAMs) and the current collector aluminum from the long list of degradation processes of lithium ion batteries affecting their safety, cycling stability and lifetime.The problem of transition metal dissolution has been evidenced already in the early 1990’s and since then has been investigated by many groups. While the loss of the active material itself plays only a minor role, the deposition of released metal ions on the graphite anode with the associated increased impedance and loss of active lithium impairs mainly the specific capacity retention. Although essential for effective prevention, the underlying mechanism of this process is not fully understood. The vast majority of investigations is based on ex situ and post mortem analysis of cycled battery cells or on simple tests probing the effect of various extra-electrochemical experimental conditions on the stability of CAMs. These type of studies can, however, not give a thorough insight into the potential dependent dissolution mechanisms and cannot judge the effect of chemical modifications on the stability of cells rapidly. There exists only few in situ methods for such investigations, which require the use of huge research facilities (like synchrotron radiation).Aluminum is the choice of material in state-of-the-art batteries for cathode current collector. This metals can undergo severe dissolution processes as well, and therefore, it is essential to understand the underlying mechanisms in order to propose reliable solutions to mitigate this problem. The consequences of these processes are not just the passivation of active material areas due to the loss of electrical contact but higher self-discharge rate through the ion contaminations in the electrolytes and impedance growth due to the deposition of dissolved ions on the anode SEI altering its structure and functioning, similarly to the effect of transition metals. These consequences all lead to capacity fade and decrease of specific energy.We have developed an electroanalytical flow cell (EFC) coupled to an ICP-MS, which is suitable for the use in aggressive nonaqueous electrolytes. Furthermore, the EFC is operated in an argon filled glovebox, which allows otherwise unattainably strict control of experimental conditions, like the water content of electrolytes [1,2]. In this contribution we give insights in the features of the EFC-ICP-MS method. Furthermore, the intrinsic stability of a state-of-the-art layered transition metal oxide cathode material LiNi0.8Co0.1Mn0.1O2 and of aluminum is characterized by on-line monitored time- and potential-resolved dissolution profiles. Special attention is paid to the influence of varying test procedures such as upper and lower cut off potentials and scan / C-rates on the onset potential of the dissolution and curve progression. In addition, we relate the amount of dissolved transition metal ions measured with the EFC-ICP-MS setup to data reported in the literature and own ex-situ analysis results. In case of Al, we give an insight into the effect of LiPF6 on the stability of the metal based on the analysis of data from single potential cycles.Literature:[1] J. Ranninger et al., Electrochem. Comm., 2020, 114, 106702[2] J. Ranninger et al., J. Electrochem. Soc., 2020, 167, 121507

Investigation of the cyclic aging characteristics and degradation mechanism of LiNi1/3Co1/3Mn1/3O2 batteries by non-invasive methodologies

Cyclic aging tests of LiNi1/3Co1/3Mn1/3O2 batteries are performed at 25℃, 45℃ and 60℃. Several non-invasive electrochemical techniques, such as incremental capacity analysis, differential voltage analysis and capacity difference analysis, are employed to deduce degradation mechanism. The degradation mechanism of batteries is similar at different temperatures. Loss of active positive material follows a linear function at all conditions and increases by elevating temperature. Due to the graphite's volume expansion and contraction, loss of active negative material is observed at the first 100 full cycle equivalents. Then, it disappears until the appearance of a dense lithium-containing passivation layer. This covering layer is mainly from lithium deposition on the negative electrode surface. With this lithium-impermeable covering layer's growth, the homogeneity of active lithium distribution is successively reduced, and loss of negative material increases gradually. Moreover, a worst cyclic performance is found at 45℃, where the homogeneity of electrodes reduces rapidly. All results reveal that loss of active materials and lithium inventory loss only influence capacity loss. The evolution of the covering layer on the negative electrode surface is the deciding factor for cycle life.

Enhancing high rate performance and cyclability of LiFePO4 cathode materials for lithium ion batteries by boron doping

The application of olivine-type LiFePO4 as cathode material for lithium-ion batteries is hampered by its low electronic conductivity and slow lithium-ion diffusion coefficient. To settle these problems, many efforts focus on cation substitution on Li or Fe-site. Here, we fabricated boron doped LiFePO4 on P-site, LiFeP1−xBxO4-δ/C (x = 0, 0.01, 0.02, 0.04), via a normal solvothermal routine. In this work, the proper amounts adding of B can refine crystal size, improve dispersity, decrease charge transfer resistance, increase electronic conductivity, enhance the mobility of lithium ions, so as to modify its cycling and rate capability. For this reason, the LiFeP0.98B0.02O4-δ/C shows the excellent electrochemical performance among all investigated samples, which delivers the first discharge capacity of 138 mAh g−1 at 2 C with no evident capacity fading after 300 cycles. Even at 10C, it still reveals a high discharge capacity of 110 mAh g−1. It is also found that the excessive doping of B could lead to oxygen defects in the material, resulting in the decrease of active lithium and unfavorable electrochemical property. Our work not only states the significance of B doping with different contents, but also provides a promising opportunity to design of cathode materials with superior performance.

Pressure Prediction Modeling and Validation for Lithium-Ion Pouch Cells in Buffered Module Assemblies

Lithium-ion pouch cells must be constrained for optimal performance and lifetime. By introducing buffer layers to the module, beneficial medium pressures can be maintained over long aging periods. In this work, we review the irreversible cell growth mechanism for an automotive cell by multifaceted post-mortem analysis. Quantitative analysis of scanning electron imaging, growth and compression data as well as elemental analysis reveal anode dominated growth attributed to solid electrolyte interphase growth and thus correlated to loss of active lithium for aged cells. Based on this, a relaxed 1D force equilibrium model is developed that may predict module pressures both at begin-of-life and over aging for buffered and unbuffered module assemblies. The pressure evolution predictions over lifetime for both module types are successfully validated by optical ex-situ measurements of 22 modules aged on system level. The presented framework may guide pouch-type module design choices and engineering tradeoffs to optimize energy density, safety, stability, lifetime and performance.

Mechanistic Insights into the Pre‐Lithiation of Silicon/Graphite Negative Electrodes in “Dry State” and After Electrolyte Addition Using Passivated Lithium Metal Powder

AbstractBecause of its high specific capacity, silicon is regarded as the most promising candidate to be incrementally added to graphite‐based negative electrodes in lithium‐ion batteries. However, silicon suffers from significant volume changes upon (de‐)lithiation leading to continuous re‐formation of the solid electrolyte interphase (SEI) and ongoing active lithium losses. One prominent approach to compensate for active lithium losses is pre‐lithiation. Here, the “contact pre‐lithiation” of silicon/graphite (Si/Gr) negative electrodes in direct contact with passivated Li metal powder (PLMP) is studied, focusing on the pre‐lithiation mechanism in “dry state” and after electrolyte addition. PLMP is pressed onto the electrode surface to precisely adjust the degree of pre‐lithiation (25%, 50%, and 75%). By in situ XRD and ex situ 7Li NMR studies, it is proven that significant lithiation of Si/Gr electrodes occurs by direct contact to Li metal, that is, without electrolyte. After electrolyte addition, de‐lithiation of silicon and graphite is confirmed, resulting in SEI formation. The amount of Li metal highly impacts the presence and durability of the LixC and LixSi phases. Finally, the challenges for homogeneous pre‐lithiation and SEI formation are identified, and the impact of electrolyte addition is assessed by analysis of the lateral and in‐depth lithium distribution within the Si/Gr electrode.

Air stable lithium microspheres prelithiation reagents for Li-ion batteries synthesized via electroplating

Prelithiation is a critical strategy in lithium-ion batteries (LIBs) to compensate the active lithium loss due to the low Coulombic efficiency (CE) caused by the formation of solid electrolyte interphase. The scarce of suitable prelithiation reagents impedes the applications of prelithiation in LIBs. Herein, ultra-fine air stable lithium spheres (ASLSs) comprised of a metallic lithium core and a LiF/Li2O shell are produced via a facile electrochemical plating technique. The LiF/Li2O shell efficiently protects the ASLSs in air, and the uniform small size endows the ASLSs high prelithiation performance for anodes such as graphite, SiO@C and Sn@C. The CE of the ASLSs prelithiated graphite electrode (PG) is improved from 77.4% to 101.9%. The energy density of the PG/LiCoO2 full cell is significantly improved. The ASLSs prelithiated SiO@C and Sn@C electrodes also significantly improve the first-cycle CEs. In-situ transmission electron microscopy studies indicate that stress induced creep of metallic lithium plays the dominant role in the formation of well-defined ASLSs. This study provides a simple technique to synthesize an efficient prelithiation reagent for LIBs.

A Thorough Analysis of Two Different Pre‐Lithiation Techniques for Silicon/Carbon Negative Electrodes in Lithium Ion Batteries

AbstractSilicon (Si) is one of the most promising candidates for application as high‐capacity negative electrode (anode) material in lithium ion batteries (LIBs) due to its high specific capacity. However, evoked by huge volume changes upon (de)lithiation, several issues lead to a rather poor electrochemical performance of Si‐based LIB cells. The Coulombic efficiency (CEff) during the first cycle(s), especially when using nano‐sized Si, is relatively low, due to the formation of the solid electrolyte interphase (SEI). Pre‐lithiation approaches can increase the CEff by compensating active lithium losses during the first cycle(s). Here, we evaluate the beneficial impact of pre‐lithiated Si/C electrodes for their application in NCM111||Si/C cells by comparing two approaches, i. e., electrochemical pre‐lithiation and pre‐lithiation by direct contact to Li metal foil. The SEI composition and surface morphology of pre‐lithiated Si/C electrodes as well as the impact of reducing active Li losses on individual electrode potentials over cycling are revealed. For long‐term cycling, both pre‐lithiation techniques lead to a distinct improvement of the overall capacity as well as the CEff for the first 40 cycles due to i) the pre‐formed SEI and ii) a Li reservoir within the anode. Depletion of the active Li from NCM111 is significantly reduced and we can confirm that both pre‐lithiation techniques improve the cycling performance of NCM111||Si/C cells in an almost equal manner.

Effects of charging protocols on the cycling performance for high-energy lithium-ion batteries using a graphite-SiOx composite anode and Li-rich layered oxide cathode

High-energy lithium-ion batteries (LIBs) using Si-based anode and Li-rich layered oxide (LLO) cathode suffer severe capacity degradation during cycling, which is directly affected by the charging protocols. In this paper, the effect of constant current (CC) and constant current-constant voltage (CC-CV) charging on the cycling performance of graphite-SiOx/LLO pouch-type batteries is studied. Unexpectedly, after 300 cycles, the batteries under the CC-CV protocol show capacity retention of 71.22%, batteries under the CC protocol, however, show capacity retention of only 64.02%. For the batteries using the CC protocol, the electrochemical test results reveal an unstable change in the electrode/electrolyte interface resistance and bigger lithium ion diffusion resistance. The postmortem analyses further indicate a solid electrolyte interface (SEI) film with lower chemical stability and a greater loss of active lithium and Si in the anode. Compared with the CC protocol, the batteries under the CC-CV protocol possess a more stable SEI film and a smaller loss of active lithium and Si. This work has certain reference significance for optimizing the charging protocol.

Nonporous Gel Electrolytes Enable Long Cycling at High Current Density for Lithium-Metal Anodes.

Lithium-metal anodes with high theoretical capacity and ultralow redox potential are regarded as a "holy grail" of the next-generation energy-storage industry. Nevertheless, Li inevitably reacts with conventional liquid electrolytes, resulting in uneven electrodeposition, unstable solid electrolyte interphase, and Li dendrite formation that all together lead to a decrease in active lithium, poor battery performance, and catastrophic safety hazards. Here, we report a unique nonporous gel polymer electrolyte (NP-GPE) with a uniform and dense structure, exhibiting an excellent combination of mechanical strength, thermal stability, and high ionic conductivity. The nonporous structure contributed to a uniform distribution of lithium ions for dendrite-free lithium deposition, and Li/NP-GPE/Li symmetric cells can maintain an extremely low and stable polarization after cycling at a high current density of 10 mA cm-2. This work provides an insight that the NP-GPE can be considered as a candidate for practical applications for lithium-metal anodes.

Pre-Lithiation Strategies for Next-Generation Practical Lithium-Ion Batteries.

Next‐generation Li‐ion batteries (LIBs) with higher energy density adopt some novel anode materials, which generally have the potential to exhibit higher capacity, superior rate performance as well as better cycling durability than conventional graphite anode, while on the other hand always suffer from larger active lithium loss (ALL) in the first several cycles. During the last two decades, various pre‐lithiation strategies are developed to mitigate the initial ALL by presetting the extra Li sources to effectively improve the first Coulombic efficiency and thus achieve higher energy density as well as better cyclability. In this progress report, the origin of the huge initial ALL of the anode and its effect on the performance of full cells are first illustrated in theory. Then, various pre‐lithiation strategies to resolve these issues are summarized, classified, and compared in detail. Moreover, the research progress of pre‐lithiation strategies for the representative electrochemical systems are carefully reviewed. Finally, the current challenges and future perspectives are particularly analyzed and outlooked. This progress report aims to bring up new insights to reassess the significance of pre‐lithiation strategies and offer a guideline for the research directions tailored for different applications based on the proposed pre‐lithiation strategies summaries and comparisons.

A Scalable Cathode Chemical Prelithiation Strategy for Advanced Silicon-Based Lithium Ion Full Batteries.

A silicon anode with ultra-high specific capacity has motivated tremendous exploration for high-energy-density lithium ion batteries while it still faces serious issues of irreversible lithium loss, unstable electrode electrolyte interface (SEI), and huge volume expansion. Prelithiation is a crucial technology to alleviate the harm of active lithium loss of silicon-based full-cell systems. Herein, we reported a cathode prelithiation method using Li2S-PAN as a lithium "donor", which was synthesized via chemical reaction between sulfurized polyacrylonitrile and Li-biphenyl complex. The Li2S-PAN with an initial charging capacity of 668 mAh g-1 (2.5-4.0 V) is loaded on the LiFePO4 electrode, and the LiFePO4/Li2S-PAN composite electrode displays a high initial charge capacity of 206 mAh g-1, which is 22.3% higher than the pristine LiFePO4. With a silicon/graphite/carbon (Si/G/C) composite anode, the Si/G/C||LiFePO4/Li2S-PAN full cell exhibits a reversible capacity of 123 and 107 mAh g-1 in the 1st and 10th cycle, which is 15.5 and 24.5% higher than the Si/G/C||LiFePO4 battery, respectively. The SEI layer of the silicon anode in the Si/G/C||LiFePO4/Li2S-PAN cell contains abundant conductive LiF species, which can enhance the interfacial stability and reaction kinetics of the cells. The proposed cathode prelithiation process is compatible with the industrial roll-to-roll electrode preparation process, exhibiting a promising application prospect.