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The development of better batteries is of utmost importance for our economy. Batteries based on lithium metal promise a much higher energy density than the lithium ion batteries common today, where the ions are stored in graphite, which adds extra weight. However, lithium metal batteries are plagued by the formation  of dendrites, which can short‐circuit the battery and set it on fire. Much theoretical effort has been spent on the causes of dendrite formation, but a decisive factor has been overlooked: Lithium is deposited on an electrode which carries a sizable negative charge, and this charge is not distributed homogeneously on the surface. We show by explicit model calculations, that the excess charge accumulates on small protrusions and creates a strong electric field, which attracts the Li$^+$ ions, induces further growth on the tip and finally the formation of dendrites.   Even a small tip consisting of a few atoms will carry an excess charge of a tenth of a unit charge or more. In addition, the negative charge on the tips locally  reduces the surface tension, which further fosters dendrite growth. The same principles can also explain dendrite formation on other metals with deposition potentials below the potential of zero charge.

The effect of exchange current density on electrodeposition behavior of lithium (Li) is revealed by a phase‐field modeling and validated by experimental data. The results show that lower exchange current density contributes to uniform distribution of cathodic current density and formation of nuclei with larger critical radius, two factors that promote dense Li deposition, high Coulombic efficiency, and dendrite‐free morphology.

Abstract

Due to an ultrahigh theoretical specific capacity of 3860 mAh g⁻¹, lithium (Li) is regarded as the ultimate anode for high‐energy‐density batteries. However, the practical application of Li metal anode is hindered by safety concerns and low Coulombic efficiency both of which are resulted fromunavoidable dendrite growth during electrodeposition. This study focuses on a critical parameter for electrodeposition, the exchange current density, which has attracted only little attention in research on Li metal batteries. A phase‐field model is presented to show the effect of exchange current density on electrodeposition behavior of Li. The results show that a uniform distribution of cathodic current density, hence uniform electrodeposition, on electrode is obtained with lower exchange current density. Furthermore, it is demonstrated that lower exchange current density contributes to form a larger critical radius of nucleation in the initial electrocrystallization that results in a dense deposition of Li, which is a foundation for improved Coulombic efficiency and dendrite‐free morphology. The findings not only pave the way to practical rechargeable Li metal batteries but can also be translated to the design of stable metal anodes, e.g., for sodium (Na), magnesium (Mg), and zinc (Zn) batteries.

Prelithiated alloy anodes undergo spontaneous structure evolution upon electrochemical dealloying, which is expected to have significant influence on cell performance. Herein, Li‐Ag foils are fabricated as a case study to understand the detailed delithiation/lithiation process. It is revealed that the evolved bicontinuous structure affords good cycling stability with high Li utilization and marginal volume variation.

Abstract

Dealloying is a powerful technology to fabricate nanoporous materials with tunable structures and compositions for battery applications. Meanwhile, electrochemical dealloying is an intrinsic process for metal anodes that exhibits fundamental correlations with electrode morphologies and structures. In this work, Li‐Ag composites are fabricated as a case study to understand the spontaneous structural evolution and the in situ formation of nanoporosity during a reversible lithiation/delithiation process. The rationally designed nanoporous AgLi (NPAgLi) framework with limited Li capacity (10 mAh cm⁻²) enables a dendrite‐free anode with marginal volume variation upon long‐term cycling, which can be attributed to the spatially confined reaction pattern along with efficient Li alloying/dealloying. Furthermore, full cell tests reveal the NPAgLi anode remains stable under practical conditions such as lean electrolyte (15 µL), large areal capacity (1.6 mAh cm⁻²), and high‐loading cathode (12 mg cm⁻²). This work provides new perspectives on the in situ structural evolution of Li‐rich alloy electrodes and the results are expected to contribute to the development of alkali metal anodes.

A highly stable hosted Li with LiF‐dominate solid electrolyte interlayer (SEI) has been fabricated, which delivers a promoted high Coulombic efficiency, homogeneous Li deposition and ultrahigh‐rate stable cycling over 1000 cycles at 20 mA cm⁻² with a lower voltage polarization. Moreover, half cells with LiNi_0.8Co_0.1Mn_0.1O₂, sulfur or even thick LiCoO₂ demonstrate enhanced cycling stability even under lean electrolyte.

Abstract

The advanced energy storage of an Li metal substituted for graphite anode can provide a significant enhancement in a battery's energy density. Nevertheless, the practical implementation of metallic Li has seriously been fettered by the notorious Li dendrite growth and the huge volumetric variation of Li metal inducing poor cycling performance and safety concerns. In this regard, constructing a robust SEI layer combined with a 3D host to stabilize the Li metal is strongly in demand. Herein, a highly stable hosted Li with an LiF dominated SEI has successfully been achieved through metal‐free fluorinated carbon fibers (FCF) with strong lithiophilicity. The metal‐free design is cost‐effective and can retain the energy density of the Li metal, minimizing the unnecessary energy sacrifice from the extra high gravimetric density lithiophilic sites. The FCF hosted Li delivers a promoted high Coulombic efficiency, homogeneous Li deposition, and ultrahigh rate stable cycling over 1000 cycles at 20 mA cm⁻² with a much lower voltage polarization (≈220 mV). Moreover, half cells coupled with LiNi_0.8Co_0.1Mn_0.1O₂, sulfur or even thick LiCoO₂ cathode demonstrate superior rate performances and enhanced cycling stability even under a lean electrolyte. This work proves the feasibility of FCF hosted Li for practical usage and provides a novel approach toward cost‐effective and high performance lithium metal batteries.

A novel Li/Ni composite anode is obtained by combining lithium foil with a honeycombed periodic Ni mesh fabricated by laser‐direct‐writing technique. Lithium dendrites seed from Ni mesh and grow parallel with electrode/electrolyte interface, thus presenting a stable cycling performance with ultralow overpotential of 6–8 mV for over 1000 h at the current density of 0.5 mA cm⁻².

Abstract

The disordered dendritic growth of Li metal seriously hampers the practical application of lithium metal batteries. Great efforts are devoted to suppress the growth of dendrites, it is still necessary to explore measures of controlling dendritic growth and pave ways for normal cell operation in presence of dendrites. Herein, a modification technique of Li metal anode by a periodic Ni mesh with micrometer‐sized grid is proposed for interfacial engineering. Periodic patterned Ni mesh is prepared using a novel laser direct‐writing technique combined with selective electrodeposition process. The growth of Li dendrites is regulated under the effect of unique electric field distribution by the introduction of the Ni mesh. It is noteworthy that the controlled lateral growth of dendrites is successfully realized by the internal structure modification instead of any external electric or magnetic field as has been previously reported. The resultant anode exhibits a stable cycling performance with ultralow overpotential of 6–8 mV for over 1000 h at the current density of 0.5 mA cm⁻². It also presents superior electrochemical performance when assembled against LiFePO₄ cathode into full cells, with an initial capacity of 133 mA h g⁻¹ and a stable cycling performance over 160 cycles.

A liquid electrolyte composed of de-solvated Li-ions, “frozen-like” solvents and crystal-like salt solute was achieved after the de-solvation of Li-ions was occurred before enter the narrow metal-organic framework (MOF) channels (eolitic imidazolate framework-7 [ZIF-7], 2.9 Å). Benefit from this unique electrolyte configuration, the prepared “Li+-de-solvated ether electrolyte” demonstrated a largely enhanced electrochemical stability window (extended to 4.5 V) and remarkably suppressed solvents-related decomposition (CEI-free cathode surface). The prepared electrolyte can be coupled with limited Li and high-voltage cathode like NCM-811 to construct high-energy-density LMB full-cell.

The use of lithium (Li) or sodium (Na) metal anodes together with highly ion-conductive solid electrolytes (SEs) could provide batteries with a step improvement in volumetric and gravimetric energy densities. Unfortunately, these SEs face significant technical challenges, in large part because Li and Na dendrites can penetrate through SEs, leading to short circuits. The ability of such a soft material (Li or Na metal) to penetrate through ceramic is surprising from the point of view of models widely used in the Li-battery field.

Lithium‐sulfur (Li‐S) battery show application prospect as a high energy density battery system. However, lithium polysulfides (LiPSs) intermediates can easily shuttle to Li anode and severely react with Li metal, which deplete the active materials and cause the rapid failure of batteries, remaining a great barrier for their practical application. Herein, a facile solution‐pretreatment method for Li anodes with metal‐fluorides/dimethylsulfoxide solution is developed to in situ construct robust biphasic surface layers (BSLs), which are consist of lithiophilic alloy (Li x M) and LiF phases on Li metal to efficiently inhibit the shuttle effect and increase the cycle life of Li‐S batteries. The BSLs with good Li + transport ability and mechanical property can not only efficiently inhibit the dendrite growth, but also shield the Li anodes from the corrosion reaction with LiPSs. The Li‐S batteries with such BSLs‐Li anodes show the excellent cycling number over 1000 cycles at 1 C, and simultaneously maintain a high coulombic efficiency of 98.2%. Based on the experimental and theoretical results, we propose a new synergetic mechanism based on the robust BSLs and metal‐S bond repulsion‐space shield for inhibiting the shuttle effect, which is an efficient strategy for achieving high stability Li‐S batteries and other metal battery systems.

A thin film of atomic layer deposition (ALD)‐grown TiO₂ deposited on a copper current collector enables uniform and stable nucleation of lithium metal by forming a lithiophilic layer of Li _x TiO₂ and reducing the overpotential for lithium deposition. Growing atomically precise thin films on copper current collectors is a promising strategy for lithium nucleation control.

Abstract

The practical implementation of Li metal batteries is hindered by difficulties in controlling the Li metal plating microstructure. While previous atomic layer deposition (ALD) studies have focused on directly coating Li metal with thin films for the passivation of the electrode–electrolyte interface, a different approach is adopted, situating the ALD film beneath Li metal and directly on the copper current collector. A mechanistic explanation for this simple strategy of controlling the Li metal plating microstructure using TiO₂ grown on copper foil by ALD is presented. In contrast to previous studies where ALD‐grown layers act as artificial interphases, this TiO₂ layer resides at the copper–Li metal interface, acting as a nucleation layer to improve the Li metal plating morphology. Upon lithiation of TiO₂, a Li _x TiO₂ complex forms; this alloy provides a lithiophilic surface layer that enables uniform and reversible Li plating. The reversibility of lithium deposition is evident from the champion cell (5 nm TiO₂), which displays an average Coulombic efficiency (CE) of 96% after 150 cycles at a moderate current density of 1 mA cm⁻². This simple approach provides the first account of the mechanism of ALD‐derived Li nucleation control and suggests new possibilities for future ALD‐synthesized nucleation layers.

A fundamental understanding of dendrite formation and dissolution mechanisms is an important issue for Li metal batteries. This progress report summarizes recent work on the mechanistic understanding of Li deposition and dissolution by in situ/operando analytical techniques using light, electron, X‐ray, neutron, and magnetism‐based characterizations, highlighting the critical role of in situ/operando analyses in developing stable Li metal batteries.

Abstract

Lithium, the lightest metal with the lowest standard reduction potential, has been long considered as the ultimate anode material for next‐generation high‐energy‐density batteries. However, an unexpected Li dendrite formation, which causes poor reversibility of electrochemical reactions and safety concerns, is a major problem that has to be solved for the commercialization of Li metal anodes. For the implementation of stable Li metal anodes, complete understanding on the dendritic Li formation and its dissolution is essential for electrode material design, which requires the development of advanced characterization techniques. Specifically, compared to an ex situ characterization as a postmortem analysis, in situ/operando characterizations allow dynamic structural and chemical evolution to be directly observed in a realistic battery cell, which helps unravel the complex reactions and degradation mechanisms in Li metal anodes. Here, recent progress in the understanding of electrochemical behavior in Li metal anodes upon deposition and dissolution, verified by the in situ/operando analytical techniques using light, electron, X‐ray, neutron, and magnetism‐based characterizations, is covered. This progress report provides a fundamental understanding of Li deposition and dissolution mechanisms and highlights the critical role of in situ/operando analyses in developing stable Li metal anodes.

The crystal structure of copper (Cu) impacts the growth of graphdiyne. As‐grown graphdiyne splits Cu into quantum dots. Cu quantum dots on graphdiyne have high lithiophilicity to suppress lithium dendrites. This one‐step method to produce Cu quantum dots on all‐carbon graphdiyne can be used to develop many new‐concept and high‐activity catalysts for sustainable technologies.

Abstract

As an emerging carbon allotrope, the controllable growth of graphdiyne has been an important means to explore its unique scientific properties and applications. In this work, the effect of the crystal structure of copper (Cu) on the growth of graphdiyne is systematically studied. It is found that the crystal boundaries are the origin of the reaction activity. The polycrystalline Cu nanowire with many crystal boundaries is spontaneously split into Cu quantum dots (about 3 nm) by the grown graphdiyne. These Cu quantum dots are uniformly dispersed on the graphdiyne, and they block the long‐range ordered growth of the graphdiyne. These Cu quantum dots in situ supported on graphdiyne demonstrate high efficiency in inhibiting the growth of lithium dendrites in lithium metal batteries. Based on this interesting finding, the Cu quantum dots anchored on the all‐carbon graphdiyne can be prepared on a large scale, and unique applications of Cu quantum dots in electrochemical fields can be implemented.

Solution‐processable conjugated microporous polymers are developed as protective layers for lithium anodes to achieve high‐energy‐density batteries with a long cycle life. A pouch cell fabricated using CMP‐modified lithium foil achieves an energy density exceeding 400 Wh kg⁻¹ and cycle stability >65 cycles.

Abstract

Lithium metal is the “holy grail” of anodes, capable of unlocking the full potential of cathodes in next‐generation batteries. However, the use of pure lithium anodes faces several challenges in terms of safety, cycle life, and rate capability. Herein, a solution‐processable conjugated microporous thermosetting polymer (CMP) is developed. The CMP can be further converted into a large‐scale membrane with nanofluidic channels (5–6 Å). These channels can serve as facile and selective Li‐ion diffusion pathways on the surfaces of lithium anodes, thereby ensuring stable lithium stripping/plating even at high areal current densities. CMP‐modified lithium anodes (CMP‐Li) exhibit cycle stability of 2550 h at an areal current density of 20 mA cm⁻². Furthermore, CMP is readily amenable to solution‐processing and spray coating, rendering it highly applicable to continuous roll‐to‐roll lithium metal treatment processes. Pouch cells with CMP‐Li as the anode and LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) as the cathode exhibits a stable energy density of 400 Wh kg⁻¹.

A dendrite‐free Li/carbon nanotube (CNT) hybrid has been fabricated by direct coating molten Li on CNTs for Li‐metal batteries. Favorable thermodynamic and kinetic conditions are a powerful force to drive the rapid lift upwards and infusion of molten Li into CNTs network. The obtained hybrid exhibits super‐stable function even at an ultrahigh current density.

Abstract

Lithium (Li) metal is promising in the next‐generation energy storage systems. However, its practical application is still hindered by the poor cycling performance and serious safety issues for the consequence of dendritic Li. Herein, a dendrite‐free Li/carbon nanotube (CNT) hybrid is proposed, which is fabricated by direct coating molten Li on CNTs, for Li‐metal batteries. The favorable thermodynamic and kinetic conditions are the powerful force to drive the rapid lift upwards and infusion of molten Li into CNTs network, which is the key to form a uniform metallic layer in Li/CNTs hybrid. The obtained hybrid indicates super‐stable functions even at an ultrahigh current density of 40 mA cm⁻² for 2000 cycles with a stripping/plating capacity of 2 mAh cm⁻² in symmetric cells. Subsequently, this hybrid also demonstrates a significantly decreased resistance, excellent cycling stability at high current density and flexibility in the full Li‐S battery. This work provides valuable concepts in fabricating Li anodes toward Li‐metal batteries and beyond for their high‐level services.

In article 2002193, Young Soo Yun and co‐workers review the design of 3D‐structured electrode materials for lithium‐metal anodes, which can deliver high theoretical capacity at low redox potential for rechargeable batteries. The three categories of metal‐based materials, carbon‐based materials, and their hybrids are considered.

A mechanically stable and resilient Li metal host is fabricated by covalently cross‐linking a highly conductive and lithiophilic MXene/silver nanowire scaffold, the prepared Li metal composite anodes exhibit extremely long‐term reversible Li plating–stripping at ultrahigh current densities with ultrahigh areal capacities.

Abstract

The applications of lithium metal anode are limited by uncontrollable lithium dendrite growth and infinite volume changes during cycling. These fundamental issues are exacerbated at high cycling current densities and capacities. Herein, a mechanically stable and resilient lithium metal host is fabricated by covalently cross‐linking a highly‐conductive and lithiophilic MXene/silver nanowire scaffold through a silylation reaction between MXene nanosheets and polysiloxane. Compared with the control sample (an MXene scaffold assembled by weak van der Waals forces), the covalently cross‐linked MXene scaffold displays excellent mechanical strength and resilience, which is conducive to buffer the large internal stress fluctuations generated during rapid and deep lithium plating‐stripping and guaranteed that the integrated framework structure is maintained during long‐term charging‐discharging cycles. When used in a symmetric cell, the lithium composite anode based on the covalently cross‐linked MXene host affords an unprecedented cyclic lithium plating‐stripping stability of a record‐high 3000 h lifespan at an ultrahigh current density (20 mA cm⁻²) and areal capacity (10 mAh cm⁻²). When this composite anode is coupled with a LiNi_0.5Co_0.2Mn_0.3O₂ cathode, the full cell delivers an ultrahigh rate of 10 C for up to 1000 cycles, with an average capacity decay of 0.043% per cycle and a stable Coulombic efficiency of 98.7%.

Nano‐sized Cu forms on the surface of the Cu foam host during Li loading, which exhibits a strong affinity toward Li, and effectively eliminates the formation of Li dendrites; ultimately dense Li deposition could be achieved. By adopting this strategy, a dense Li deposition is obtained. The optimized Li metal anode enhances the electrochemical performance of full cells.

Abstract

Li metal batteries have attracted extensive research attention because of their extremely high theoretical capacity. However, the commercialization of the Li metal batteries is hindered, as uncontrolled Li dendrites growth leads to safety concerns and a low coulombic efficiency. To suppress Li dendrites growth and achieve dense Li deposition, a lithiophilic 3D Cu host is designed for Li metal anode, in which the nano‐sized Cu is in situ formed with the aid of infused Li metal. The fabricated Li metal anode exhibit a superior electrochemical stability than raw Li metal anode, and compact Li is maintained during cycling. The experimental results and density functional theory calculations demonstrate that the nano‐sized Cu formed on the surface of the skeleton host shows highly exposed Cu (100) and Cu (110) surfaces, which exhibits a strong affinity toward Li, and effectively eliminates the formation of Li dendrites, leading to a dense Li deposition. With the strategy of adjusting exposed surfaces of Cu host, the optimized Li metal anode enhances the electrochemical performance of full cells, and concomitantly demonstrates their potential for future designs of next‐generation Li metal anodes or Li‐free anodes for Li metal batteries.

An in situ formed Li₂₁Si₅ alloy host prepared by a metallurgical method using low‐cost micron silicon precursor possesses very low Li diffusion barriers. The resulted Li@Li₂₁Si₅ electrode demonstrates a dendrite‐free Li deposition behavior, ensuring promising electrochemical performance.

Abstract

Performance degradation and safety issue caused by Li dendrite growth and huge volume variation hinder the practical application of Li metal anode in high‐energy‐density lithium batteries. Li diffusion barrier of the host is a key parameter that determines the dendrite growth. Herein, a stable Li₂₁Si₅ alloy host with very low Li diffusion barriers is designed and prepared by an in situ metallurgical method using low‐cost micron silicon precursor. The low diffusion barrier of Li₂₁Si₅ host enables a dendrite‐free Li deposition behavior. It is revealed that the in‐situ formed porous Li₂₁Si₅ host not only has high Li affinity, but also suppresses volume variation of the electrode effectively and thus keeps superior structural stability during Li stripping and plating processes. As a result, this new Li metal anode with Li₂₁Si₅ host exhibits promising cycle stability and rate capability with low polarization in both symmetric and full cells. This study opens new opportunities for using alloy‐based materials as the hosts for Li composite anodes.

A multilevel‐structured composite Li anode is developed to greatly lower the risk of internal short‐circuiting caused by dendrite penetration. High current density of 12 mA cm⁻² and ultra‐deep plating/stripping of 60 mAh cm⁻² are achieved in the commercial carbonate electrolyte.

Abstract

The practical application of lithium metal anode has been hindered by safety and cyclability issues due to the uncontrollable dendrite growth, especially during fast cycling and deep plating/stripping process. Here, a composite Li metal anode supported by periodic, perpendicular, and lithiophilic TiO₂/poly(vinyl pyrrolidone) (PVP) nanofibers via a facial rolling process is reported. TiO₂/PVP nanofibers with good Li affinity provide low‐tortuosity and directly inward Li⁺ transport paths to facilitate Li nucleation and deposition under high areal capacities and current densities. The micrometer‐scale interspaces between TiO₂/PVP walls offer enough space to circumvent the huge volume variation and avoid structure collapsing during the repeated deep Li plating/stripping. The unique structure enables stable cycling under ultrahigh currents (12 mA cm⁻²), and ultra‐deep plating/stripping up to 60 mAh cm⁻² with a long cycle life in commercial carbonate electrolytes. The gassing behavior in operating pouch cells is observed using ultrasonic transmission mapping. When paired with LiFePO₄ (5 mAh cm⁻²), sulfur (3 mAh cm⁻²), and high‐voltage LiNi_0.8Co_0.1Mn_0.1O₂ cathodes, the composite Li anodes deliver remarkably improved rate performance and cycling stability, demonstrating that it could be a promising strategy for balancing high‐energy density and high‐power density in Li metal batteries.

The lithium (Li) guiding matrix containing 3‐dimensional (3D) ordered bipyridinic nitrogen (N) sites introduces the uniform Li‐ion (Li⁺)flux from preoccupied Li⁺ sites attracting the Li growth direction, thus establishing the suppressed dendrite growth during the electrodeposition of Li, and the robust cycle operation of up to 900 cycle in half‐cell configuration and over 1500 h stable operation in symmetric‐cell configuration.

Abstract

Lithium (Li) metal has attracted significant attention as next‐generation anode material owing to its high theoretical specific capacity and low potential. For enabling the practical application of Li‐metal as an anode according to energy demands, suppressing dendrite growth by controlling the Li‐ion (Li⁺) is crucial. In this study, metal–organic frameworks comprising bipyridinic nitrogen linker (M‐bpyN) are proposed as 3‐dimensional (3D) Li guiding matrix. The proposed approach creates ordered electronegative functional sites that enable the preoccupied Li⁺ in the ordered bipyridine sites to produce isotropic Li growth. The Li guiding matrix containing 3D ordered bipyridinic N sites introduces preoccupied Li⁺ sites that attract the Li growth direction, thereby suppressing the dendrite growth during the electrodeposition of Li. After applying the M‐bpyN layers, stable lifespan of up to 900 cycles in the Li|M‐bpyN|Cu cell and over 1500 h of operation in the Li|M‐bpyN|Li symmetric cell is achieved. Moreover, the Li|M‐bpyN|LiFePO₄ configuration shows a long cycle retention of 350 cycles at 0.5 C. These results indicate that an M‐bpyN Li guiding matrix, which enables a uniform Li⁺ flux by 3D ordered Li⁺‐chelating sites, serve as a suitable host for Li⁺ and enhance the performance of Li‐metal electrodes.

3D TiO₂ nanotube arrays decorated using ultrafine silver nanocrystals are demonstrated as a confined space host for lithium metal deposition. Li metal anode deposited on such architecture delivers a high Coulomb efficiency at around 99.4% even after 300 cycles, ultralow overpotential of 4 mV, and long‐term cycling life over 2500 h in Li symmetric cells.

Abstract

3D scaffolds and heterogeneous seeds are two effective ways to guide Li deposition and suppress Li dendrite growth. Herein, 3D TiO₂ nanotube (TNT) arrays decorated using ultrafine silver nanocrystals (7–10 nm) through cathodic reduction deposition are first demonstrated as a confined space host for lithium metal deposition. First, TiO₂ possesses intrinsic lithium affinity with large Li absorption energy, which facilitates Li capture. Then, ultrafine silver nanocrystals decoration allows the uniform and selective nucleation in nanoscale without a nucleation barrier, leading to the extraordinary formation of lithium metal importing into 3D nanotube arrays. As a result, Li metal anode deposited on such a binary architecture (TNT‐Ag‐Li) delivers a high Coulomb efficiency at around 99.4% even after 300 cycles with a capacity of 2 mA h cm⁻². Remarkably, TNT‐Ag‐Li exhibits ultralow overpotential of 4 mV and long‐term cycling life over 2500 h with a capacity of 2 mAh cm^–2 in Li symmetric cells. Moreover, the full battery with 3D spaced Li nanotubes anode and LiFeO₄ cathode exhibits a stable and high capacity of 115 mA h g^–1 at 5 C and an excellent Coulombic efficiency of ≈100% over 500 cycles.

A multilevel‐structured composite Li anode is developed to greatly lower the risk of internal short‐circuiting caused by dendrite penetration. High current density of 12 mA cm⁻² and ultra‐deep plating/stripping of 60 mAh cm⁻² are achieved in the commercial carbonate electrolyte.

Abstract

The practical application of lithium metal anode has been hindered by safety and cyclability issues due to the uncontrollable dendrite growth, especially during fast cycling and deep plating/stripping process. Here, a composite Li metal anode supported by periodic, perpendicular, and lithiophilic TiO₂/poly(vinyl pyrrolidone) (PVP) nanofibers via a facial rolling process is reported. TiO₂/PVP nanofibers with good Li affinity provide low‐tortuosity and directly inward Li⁺ transport paths to facilitate Li nucleation and deposition under high areal capacities and current densities. The micrometer‐scale interspaces between TiO₂/PVP walls offer enough space to circumvent the huge volume variation and avoid structure collapsing during the repeated deep Li plating/stripping. The unique structure enables stable cycling under ultrahigh currents (12 mA cm⁻²), and ultra‐deep plating/stripping up to 60 mAh cm⁻² with a long cycle life in commercial carbonate electrolytes. The gassing behavior in operating pouch cells is observed using ultrasonic transmission mapping. When paired with LiFePO₄ (5 mAh cm⁻²), sulfur (3 mAh cm⁻²), and high‐voltage LiNi_0.8Co_0.1Mn_0.1O₂ cathodes, the composite Li anodes deliver remarkably improved rate performance and cycling stability, demonstrating that it could be a promising strategy for balancing high‐energy density and high‐power density in Li metal batteries.