Localized High-concentration Electrolyte Research Articles

Impact of Electrolyte on Direct-Contact Prelithiation of Silicon-Graphite Anodes in Lithium-Ion Cells with High-Nickel Cathodes.

Silicon-based anodes offer high specific capacities to enhance the energy density of lithium-ion batteries, but are severely hindered by the immense volume expansion and subsequent breakage of the solid-electrolyte-interphase (SEI) during cycling. Herein, we utilize an effective strategy, known as direct-contact prelithiation, to mitigate the challenges associated with expansion and surface instability in SiOx/graphite (SG) anodes. It involves introducing lithium into the anode via physical contact with lithium metal and electrolyte before cycling. Prelithiation of SG anodes with an advanced localized high-concentration electrolyte is shown to develop a mechanically robust artificial SEI that tolerates better the electrode volume expansion. The modified SG anode paired with the high-Ni cathode LiNi0.90Mn0.05Co0.05O2 delivers a high initial capacity of 191 mA h g-1 with 80% capacity retention over 150 cycles, compared to 46% retention with a conventional electrolyte. The bolstered SEI layer with reduced surface reactivity is due to the reduced electrolyte consumption and regulated SEI formation during cycling. Furthermore, the advanced electrolyte and fortified SG anode help reduce cathode degradation, transition-metal dissolution, and loss of active lithium. This study highlights viable prelithiation strategies to stabilize Si-based anodes for high-energy-density batteries through electrolyte design.

Stable Lithium Oxygen Batteries Enabled by Solvent-diluent Interaction in N,N-dimethylacetamide-based Electrolytes.

In the pursuit of next-generation ultrahigh-energy-density Li-O2 batteries, it is imperative to develop an electrolyte with stability against the strong oxidation environments. N,N-dimethylacetamide (DMA) is a recognized solvent known for its robust resistance to the highly reactive reduced oxygen species, yet its application in Li-O2 batteries has been constrained due to its poor compatibility with the Li metal anode. In this study, a rationally selected hydrofluoroether diluent, methyl nonafluorobutyl ether (M3), has been introduced into the DMA-based electrolyte to construct a localized high concentration electrolyte. The stable -CH3 and C-F bonds within the M3 structure could not only augment the fundamental properties of the electrolyte but also fortify its resilience against attacks from O2- and 1O2. Additionally, the strong electron-withdrawing groups (-F) presented in the M3 diluent could facilitate coordination with the electron-donating groups (-CH3) in the DMA solvent. This intermolecular interaction promotes more alignment of Li+-anions with a small amount of M3 addition, leading to the construction of an anion-derived inorganic-rich SEI that enhances the stability of the Li anode. As a result, the Li-O2 batteries with the DMA/M3 electrolyte exhibit superior cycling performance at both 30 °C (359th) and -10 °C (120th).

Toward Ultralow Temperature Lithium Metal Batteries: Advancing the Feasibility of 1,3‐Dioxolane Based Localized High‐Concentration Electrolytes via Lithium Nitrate

AbstractLithium metal batteries (LMBs) suffer severe capacity deterioration due to sluggish ionic transport kinetics at extremely low temperatures, which limits their practical operation. Selecting solvents with low desolvation energy, and promoting interfacial Li+ transport in solid electrolyte interphase (SEI) are regarded as effective methods to improve electrochemical performances. Herein, 1,3‐dioxolane (DOL) with weak solvating power is adopted for designing a DOL‐based localized high concentration electrolyte (DLHCE) with LiNO3 as a multifunctional additive. The strong coordination between NO3− and DOL molecules not only inhibits the polymerization of DOL at high lithium bis(fluorosulfonyl)imide (LiFSI) concentration, but also reduces the solvent‐diluent miscibility and extends the salt‐solvent solubility. As a result, an anion‐dominated solvation structure is obtained that derives an inorganic‐rich SEI composed of LiF and Li3N, guiding the uniform deposition of Li at low temperature. Remarkably, the Li||LiFePO4 cells retain 53.6% of room temperature capacity at −40 °C, and also present potential application of Li||NCM811 cells under cryogenic environments.

Dilutedly localized high-concentration ionogel electrolyte enabling high-voltage quasi-solid-state lithium metal batteries

Ionogels, which are being considered as quasi-solid electrolytes for energy-storage devices, exhibited technical superiority in terms of nonflammability, negligible vapor pressure, remarkable thermostability, high ionic conductivity, and broad electrochemical stability window. However, their applications in lithium metal batteries (LMBs) have been hindered by several issues: poor compatibility with Li-metal anodes and high-voltage cathodes, high viscosity, and inadequate wettability. Little attention has been paid to ionogel-based low-concentration electrolytes, despite their potential advantages in terms of Li+ mobility, viscosity, electrode wettability, and cost. Here, we demonstrate the surprising capabilities of localized high-concentration ionogel (LHCI) and dilutedly localized high-concentration ionogel (DLHCI) electrolytes, utilizing the non-solvating fluorinated ether 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, to realize high-voltage quasi-solid-state lithium metal batteries (QSLMBs). Notably, the DLHCI electrolyte not only delivers superior ionic conductivity of 3.93 × 10−3 S cm−1 but also provides a high Li plating/stripping Coulombic efficiency exceeding 99%. Moreover, it significantly enhances anodic stability when paired with 4.4 V LiNi0.8Co0.1Mn0.1O2 (NCM811) and 4.8 V LiNi0.5Mn1.5O4 (LNMO). Consequently, substantial improvement in cycling performance of QSLMBs has been realized with the DLHCI electrolyte.

Deciphering interphase instability of lithium metal batteries with localized high-concentration electrolytes at elevated temperatures

Lithium metal batteries (LMBs), when coupled with a localized high-concentration electrolyte and a high-voltage nickel-rich cathode, offer a solution to the increasing demand for high energy density and long cycle life. However, the aggressive electrode chemistry poses safety risks to LMBs at higher temperatures and cutoff voltages. Here, we decipher the interphase instability in LHCE-based LMBs with a Ni0.8Co0.1Mn0.1O2 cathode at elevated temperatures. Our findings reveal that the generation of fluorine radicals in the electrolyte induces the solvent decomposition and consequent chain reactions, thereby reconstructing the cathode electrolyte interphase (CEI) and degrading battery cyclability. As further evidenced, introducing an acid scavenger of dimethoxydimethylsilane (DODSi) significantly boosts CEI stability with suppressed microcracking. A Ni0.8Co0.1Mn0.1O2||Li cell with this DODSi-functionalized LHCE achieves an unprecedented capacity retention of 93.0% after 100 cycles at 80 °C. This research provides insights into electrolyte engineering for practical LMBs with high safety under extreme temperatures.

Sodium–Sulfur Cells with a Sulfurized Polyacrylonitrile Cathode and a Localized High Concentration Electrolyte with Toluene as a Nonfluorinated Diluent

AbstractRoom‐temperature sodium–sulfur (Na–S) batteries are recognized as promising candidates for next‐generation scalable energy storage systems due to their high energy density and cost‐effectiveness. However, several challenges persist, including the shuttle effect of polysulfide and the compatibility of sodium metal with electrolytes. Herein, the study presents a novel type of localized high‐concentration electrolyte (LHCE), utilizing a cost‐effective, low‐density nonfluorinated diluent, toluene, in contrast to the conventional fluorinated diluents. Based on density functional theory calculations and sodium stripping/plating behavior, toluene demonstrates better reduction stability than other aromatic solvents with different substitutions. Also, compared to the 1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl‐ether (TTE) diluent, toluene exhibits enhanced compatibility with sodium metal. Furthermore, it modifies the solvation structure by favoring anion‐dominated species, which contributes to the formation of a robust inorganic‐rich solid‐electrolyte interphase (SEI) with better Na‐ion transport. Consequently, Na–S cells featuring sulfurized polyacrylonitrile (SPAN) cathode with the developed LHCE exhibit good cycling stability with high capacity. The work presents a promising strategy for developing low‐cost practical Na–S batteries.

Upgrading Electrolyte Antioxidant Chemistry by Constructing Potential Scaling Relationship.

Rational design of advanced electrolytes to improve the high-voltage capability has been attracting wide attention as one critical solution to enable next-generation high-energy-density batteries. However, the limited understanding of electrolyte antioxidant chemistry as well as the lack of valid quantization approaches have resulted in knowledge gap, which hinders the formulation of new electrolytes. Herein, we construct a standard curve based on representative solvation structures to quantify the oxidation stability of ether-based electrolytes, which reveals the linear correlation between the oxidation potential and the atomic charge of the least oxidation-resistant solvent. Dictated by the regularity between solvation composition and oxidation potential, a (Trifluoromethyl)cyclohexane-based localized high-concentration electrolyte dominated by anion-less solvation structures was designed to optimize the cycling performance of 4.5 V 30 μm-Li||3.8 mAh cm-2-LiCoO2 batteries, which maintained 80 % capacity retention even after 440 cycles. The consistency of experimental and computational results validates the proposed principles, offering a fundamental guideline to evaluate and design aggressive electrochemical systems.

Dual-Salts Localized High-Concentration Electrolyte for Li- and Mn-Rich High-Voltage Cathodes in Lithium Metal Batteries.

Limited electrochemical stability windows of conventional carbonate-based electrolytes pose a challenge to support the Lithium (Li)- and manganese (Mn)-rich (LMR) high-voltage cathodes in rechargeable Li-metal batteries (LMBs). To address this issue, a novel localized high-concentration electrolyte (LHCE) composition incorporating LiPF6 and LiTFSI as dual-salts (D-LHCE), tailored for high-voltage (>4.6Vvs.Li) operation of LMR cathodes in LMBs is introduced. 7Li nuclear magnetic resonance and Raman spectroscopy revealed the characteristics of the solvation structure of D-LHCE. The addition of LiPF6 provides stable Al-current-collector passivation while the addition of LiTFSI improves the stability of D-LHCE by producing a more robust cathode-electrolyte interphase (CEI) on LMR cathode and solid-electrolyte interphase (SEI) on Li-metal anode. As a result, LMR/Li cell, using the D-LHCE, achieved 72.5% capacity retention after 300 cycles, a significant improvement compared to the conventional electrolyte (21.9% after 100 cycles). The stabilities of LMR CEI and Li-metal SEI are systematically analyzed through combined applications of electrochemical impedance spectroscopy and distribution of relaxation times techniques. The results present that D-LHCE concept represents an effective strategy for designing next-generation electrolytes for high-energy and high-voltage LMB cells.

Electrolyte‐Enabled High‐Voltage Operation of a Low‐Nickel, Low‐Cobalt Layered Oxide Cathode for High Energy Density Lithium‐Ion Batteries

AbstractThe lithium‐ion battery industry acknowledges the need to reduce expensive metals, such as cobalt and nickel, due to supply chain challenges. However, doing so can drastically reduce the overall battery energy density, attenuating the driving range for electric vehicles. Cycling to higher voltages can increase the capacity and energy density but will consequently exacerbate cell degradation due to the instability at high voltages. Herein, an advanced localized high‐concentration electrolyte (LHCE) is utilized to enable long‐term cycling of a low‐Ni, low‐Co layered oxide cathode LiNi0.60Mn0.31Co0.07Al0.02O2 (NMCA) in full cells with graphite or graphite‐silicon anodes at 4.5 V (≈4.6 vs Li+/Li). NMCA cells with the LHCE deliver a high initial capacity of 194 mA h g−1 at C/10 rate along with 73% capacity retention after 400 cycles compared to 49% retention in a baseline carbonate electrolyte. This is facilitated by reduced impedance growth, active material loss, and gas evolution with the NMCA cathode. These improvements are attributed to the formation of robust, inorganic‐rich interphase layers on both the cathode and anode throughout cycling, which are induced by a favorable salt decomposition in the LHCE. This study demonstrates the efficacy of electrolytes toward facilitating the operation of high‐energy‐density, long‐life, and cost‐effective cathodes.

Regulate the Solvation Structure and Interface by Nitrate in Phosphate-Based Electrolytes for 4.5V-Class Ni-Rich Batteries.

Phosphate-based electrolyte propels the advanced battery system with high safety. Unfortunately, restricted by poor electrochemical stability, it is difficult to be compatible with advanced lithium metal anodes and Ni-rich cathodes. To alleviate these issues, the study has developed a phosphate-based localized high-concentration electrolyte with a nitrate-driven solvation structure, and the nitrate-derived N-rich inorganic interface shows excellent performance in stabilizing the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode interface and modulating the lithium deposition morphology on the anode. The results show that the Li|| NCM811 cell has exceptional long-cycle stability of >80% capacity retention after 800 cycles at 4.3V, 1 C. A more prominent capacity retention rate of 93.3% after 200 cycles can be reached with the high voltage of 4.5V. While being compatible with the phosphate-based electrolyte with good flame retardancy and the good electrochemical stability of Ni-rich lithium metal battery (LMBs) systems, the present work expands the construction of anion-rich solvation structures, which is expected to promote the development of the high-performance LMBs with safety.

Localized High-Concentration Sulfone Electrolytes with High-Voltage Stability and Flame Retardancy for Ni-Rich Lithium Metal Batteries.

The localized high-concentration electrolyte (LHCE) propels the advanced high-voltage battery system. Sulfone-based LHCE is a transformative direction compatible with high energy density and high safety. In this work, the application of lithium bis(trifluoromethanesulphonyl)imide and lithium bis(fluorosulfonyl)imide (LiFSI) in the LHCE system constructed from sulfolane and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) is investigated. The addition of diluent causes an increase of contact ion pairs and ionic aggregates in the solvation cluster and an acceptable quantity of free solvent molecules. A small amount of LiFSI as an additive can synergistically decompose with TTE on the cathode and participate in the construction of both electrode interfaces. The designed electrolyte helps the Ni-rich system to cycle firmly at a high voltage of 4.5V. Even with high mass load and lean electrolyte, it can keep a reversible specific capacity of 91.5% after 50 cycles. The constructed sulfone-based electrolyte system exhibits excellent thermal stability far beyond the commercial electrolytes. Further exploration of in-situ gelation has led to a quick conversion of the designed liquid electrolyte to the gel state, accompanied by preserved stability, which provides a direction for the synergistic development of LHCE with gel electrolytes.

The high-fluorinated bi-molecular combination enables high-energy lithium batteries under challenging environment

The drawbacks of temperature sensitivity, high voltage intolerance, and flammability of lithium batteries are gradually brought to light in conventional carbonate electrolytes. To solve these problems, a localized high concentration electrolyte (LHCE) employing highly fluorinated ethyl trifluoroacetate (TFAE) and 2,2,3,3-tetrafluoro-1-(1,1,2,2-tetrafluoroethoxy) propane (TFEP) is designed. When applied in high-energy lithium batteries, the discharge specific capacity of Li||NMC811 battery can maintain 143.6 mAh/g after 500 cycles at 4.6 V and 1C, and the capacity retention of Li||LNMO battery retains as high as 89.99 % after 500 cycles at 5 V. In addition, this LHCE also possesses the ability to operate the battery under challenging conditions including low temperature, fast charge, safety risks, etc. The LHCE based on TFAE and TFEP has unique solvated structures to generate a moderate LiF-rich interfacial layer, ensuring the fast Li+ migration. This work will provide strong guidance for future electrolyte industrial design of high-energy lithium battery.

Stable room-temperature sodium-sulfur battery enabled by pre-sodium activated carbon cloth anode and nonflammable localized high-concentration electrolyte

Room-temperature (RT) sodium-sulfur (Na–S) battery is a promising energy storage technology with low-cost, high-energy-density and environmental-friendliness. However, the current RT Na–S battery suffers from various problems, such as poor cycling stability and poor electrolyte-electrode compatibility caused by polysulfide shuttling and active Na-metal anode. Here, a nonflammable localized high-concentration electrolyte (LHCE) (sodium bis(trifluoromethanesulfonyl)imide salt, sulfolane solvent and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether diluent in a molar ratio of 1:2:2), and a pre-sodium activated carbon cloth (NaACC) anode, are combined to enable stable and high-safety RT Na–S battery. In LHCE, the shuttle effect of polysulfide is greatly alleviated, a stable anions-derived NaF-rich cathode electrolyte interphase is formed, and a solid-solid conversion mechanism of a solid S8-solid Na2Sn (1 ≤ n ≤ 3) is achieved. Meanwhile, the Na dendrites and side reactions between electrolyte and anode are effectively inhibited by using NaACC anode. Therefore, under the synergistic effect of electrolyte regulation and negative electrode structure optimization, although using a low N/P ratio of 1.7, the RT Na–S battery also delivers a high initial capacity of 1220.8 mAh g−1, good rate capability and stable cycling performance with a high average Coulombic efficiency of 99.1 %. The capacity still remains at 704.5 mAh g−1 after 100 cycles. This innovative combination of LHCE and NaACC anode in Na–S batteries provides a new idea for further achieving stable RT Na–S batteries with long-cycle-life and high-safety.

Enhanced Electrochemical Performance of Disordered Rocksalt Cathodes in a Localized High‐Concentration Electrolyte

Enhanced Electrochemical Performance of Disordered Rocksalt Cathodes in a Localized High‐Concentration Electrolyte

Empowering the Potassium-Sulfur Battery with Commendable Reaction Kinetics and Capacity Output by Localized High-Concentration Electrolytes.

Potassium-sulfur (K-S) batteries are one of the promising high-energy-density candidates beyond current lithium-ion batteries. Nevertheless, in practice, the utilization of K-S batteries is largely hindered due to the dissolution and shuttle effect of the cathode redox intermediates and the scarcity of an effective anode protection layer in conventional electrolytes. Herein, electrolyte engineering is applied to formulate an ether-based localized high-concentration electrolyte (LHCE) for the first time in a K-S cell with the mitigated parasitic effect of polysulfide dissolution and shuttle and the tuned anode-electrolyte interface property. A nonsolvating and polysulfide-stable fluoroether is sieved as a cosolvent in such an LHCE, which possesses the ultralow polysulfides solubility due to less roaming solvents and thus alleviates the polysulfides shuttle effect. The anion-derived solid electrolyte interphase enriched in inorganic components is constructed due to the strengthened cation-anion interplay in the primary solvation sheath and highlighted with accelerated interfacial kinetics in a K-S cell. It is validated that the proposed LHCE unlocks the theoretical capacity of the K-S cell based on the conversion between S and K2S3. It is further revealed that the lifespan is limited to the anode corrosion with severe cosolvent degradation caused by limited solvating solvent compatibility with metallic K, and the inevitable byproduct accumulation at the S cathode. The K-S cell based on the designed LHCE could achieve a prolonged lifespan with a reversible capacity of 448 mA h/gs after 80 cycles with an elaborate cathode design. This work shines a light on the electrolyte design perspective for full utilization and an in-depth mechanistic understanding of high-energy-density K-S batteries.

Additive-Driven Nanoscale Architecture of Solid Electrolyte Interphase Revealed by Cryogenic Transmission Electron Microscopy.

In Li metal batteries (LMBs), which boast the highest theoretical capacity, the chemical structure of the solid electrolyte interphase (SEI) serves as the key component that governs the growth of reactive Li. Various types of additives have been developed for electrolyte optimization, representing one of the most effective strategies to enhance the SEI properties for stable Li plating. However, as advanced electrolyte systems become more chemically complicated, the use of additives is empirically optimized. Indeed, their role in SEI formation and the resulting cycle life of LMBs are not well-understood. In this study, we employed cryogenic transmission electron microscopy combined with Raman spectroscopy, theoretical studies including molecular dynamics (MD) simulations and density functional theory (DFT) calculations, and electrochemical measurements to explore the nanoscale architecture of SEI modified by the most representative additives, lithium nitrate (LiNO3) and vinylene carbonate (VC), applied in a localized high-concentration electrolyte. We found that LiNO3 and VC play distinct roles in forming the SEI, governing the solvation structure, and influencing the kinetics of electrochemical reduction. Their collaboration leads to the desired SEI, ensuring prolonged cycle performance for LMBs. Moreover, we propose mechanisms for different Li growth and cycling behaviors that are determined by the physicochemical properties of SEI, such as uniformity, elasticity, and ionic conductivity. Our findings provide critical insights into the appropriate use of additives, particularly regarding their chemical compatibility.

Strongly solvating triglyme-based electrolyte realizes stable lithium metal batteries at high-voltage and high-temperature

The electrolyte in lithium-metal batteries (LMBs) plays a pivotal role in stabilizing the surface of the lithium metal anode (LMA) and high-voltage cathode. However, currently widely studied ether-based electrolytes, although it has good compatibility with LMA due to their lower reactivity, are facing significant challenges related to poor oxidation resistance and cathode/electrolyte interface (CEI) instability when combined with the high-voltage cathode, particularly at elevated temperatures. Therefore, there is an urgent need to design advanced electrolytes capable of maintaining high stability under high-voltage and high-temperature conditions. Here, we have developed an ultra-stable localized high-concentration electrolyte (LHCE) by introducing triethylene glycol dimethyl ether (TG), which exhibits strong solvation ability. Computational and experimental results demonstrate that the designed TG-based dilute high-concentration electrolyte (TG-DHCE) possesses a stable solvation structure, high oxidation resistance, and thermal stability, making it ideal for LMBs. Furthermore, the unique solvation structure of TG-DHCE promotes the preferential decomposition of anions while facilitating the formation of stable, inorganic-rich electrode/electrolyte interfaces on the anode and cathode. Consequently, equipped with TG-DHCE, Li||Li cells (more than 1600 h) and Li||NCM523 cells (80.6%, 250 cycles) show superior stability and also demonstrate remarkable performance even at elevated temperatures (60 °C). Additionally, under the harsh conditions of ultrahigh loading NCM523 cathode (19.7 mg/cm2) and limited Li reservoir (twice excess Li was deposited on Cu, Li@Cu) (N/P = 2), Li@Cu||NCM523 cells still maintain stable operation. This work pioneers a new path by choosing strongly solvating solvents, effectively enhancing the cycle life of LMBs under high-voltage and high-temperature conditions.

Revealing the key role of non-solvating diluents for fast-charging and low temperature Li-ion batteries

Fast-charging and low temperature operation are of vital importance for the further development of lithium-ion batteries (LIBs), which is hindered by the utilization of conventional carbonate-based electrolytes due to their slow kinetics, narrow operating temperature and voltage range. Herein, an acetonitrile (AN)-based localized high-concentration electrolyte (LHCE) is proposed to retain liquid state and high ionic conductivity at ultra-low temperatures while possessing high oxidation stability. We originally reveal the excellent thermal shielding effect of non-solvating diluent to prevent the aggregation of Li+ solvates as temperature drops, maintaining the merits of fast Li+ transport and facile desolvation as at room temperature, which bestows the graphite electrode with remarkable low temperature performance (264 mA h g−1 at −20 °C). Remarkably, an extremely high capacity retention of 97% is achieved for high-voltage high-energy graphite||NCM batteries after 250 cycles at −20 °C, and a high capacity of 110 mA h g−1 (71% of its room-temperature capacity) is retained at −30 °C. The study unveils the key role of the non-solvating diluents and provides instructive guidance in designing electrolytes towards fast-charging and low temperature LIBs.

Cycling performance of Li metal anode in localized high concentration electrolyte and dynamic mechanism analysis

In this work, we investigated the apparent cycling performance of lithium metal at different chemical compositions and series current densities; examined the microscopic morphology and thickness variation of the deposition layer on the surface of lithium metal anode and the concentration-depth distribution of trace elements in the solid electrolyte interphase (SEI) film; and characterized the kinetic behavior and features of the elementary steps (mass transfer, charge transfer, electro-crystallization) at Li-electrolyte interface using microelectrode technology and various electrochemical test methods. The results show that the lithium metal anode has better cycling performance in high concentration and localized high concentration electrolyte. At the same time, the experimental results confirm that the formation of spherical crystal nucleus is favored only under certain chemical conditions and certain reaction rate; under these conditions, the induction period and the self-smoothing process of critical crystal nucleus can be found. It suggests that there are determined causal among the apparent performance of lithium metal anode, the kinetic parameters of the interfacial charge transfer step and the electro-crystallization step, and these correlations can be used as a reference for screening and evaluating electrolyte systems and battery operating conditions, providing a reliable kinetic basis for future work.

Efficient Lithium Transport and Reversible Lithium Plating in Silicon Anodes: Synergistic Design of Porous Structure and LiF‐Rich SEI for Fast Charging

AbstractSilicon (Si) anodes hold great promise for enhancing the energy density of lithium‐ion batteries (LIBs). However, issues such as slow intrinsic kinetics and unstable interfaces caused by significant volume changes hinder the practical deployment of Si anodes. Fast charging is desired by Si‐related issues that worsen Li plating and dead Li, making it essential to overcome these for safe, reversible charging. Herein, a novel approach is proposed by combining structural design and solid electrolyte interface (SEI) modulation to enable efficient and safe fast charging of LIBs. 3D porous micro‐particles consisting of Si nanosheets coated with a pitch‐based carbon layer are successfully prepared. This design provides enhanced ion transport pathways while maintaining the material's intrinsic rate performance and tap density. Furthermore, the designed localized high‐concentration electrolyte (LHCE) exhibits a lower Li+ desolvation energy barrier and leads to the formation of a LiF‐rich SEI, mitigating the Li plating “tip effect” during fast charging, maintaining interface stability, and demonstrating high Coulombic efficiency. Overall, this study highlights the synergistic importance of structure design and SEI regulation in enhancing LIB anodes for fast charging, aiding in developing superior, safe energy storage.