Dendrite-free Lithium Research Articles

Porous transition metal oxide scaffold implanted with interpenetrated catalytic network enabling polysulfides restricted and dendrite free Lithium–Sulfur batteries

The exploration of porous polar hosts with good structural stability, high catalytic activity, lithophilic nature, and high-conductivity is desirable to solve the dilatory polysulfide redox kinetics and the uncontrolled lithium dendrite growth for efficient and stable lithium–sulfur (Li–S) batteries. Herein, a novel hierarchical metal oxide-based scaffold is developed, in which N-doped carbon nanotubes encapsulated with Co nanoparticles are in-situ implanted within three-dimensional ordered macroporous Co-doped TiO2 (Co@NCNTs/Co-TiO2) as efficient hosts for both sulfur and Li electrodes. Benefiting from the excellent stability of polar Co-TiO2 skeleton, high catalytic activity and lithophilic properties of Co nanoparticles, and high-conductivity of the inter-penetrated NCNTs, the polysulfide conversion kinetics are dramatically boosted, and the dendrite-free lithium electrochemistry is simultaneously accomplished. Cooperatively, the Co@NCNTs/Co-TiO2/Li ‖ Co@NCNTs/Co-TiO2/S full cell expresses high rate capability of 879.66 mAh g−1 at 5C, as well as super cycling stability with a low capacity decay rate of about 0.033 % after 1000 cycles at 3C. Additionally, Li–S pouch cell assembled by Co@NCNTs/Co-TiO2/Li anode and Co@NCNTs/Co-TiO2/S cathode also exhibits a remarkable discharge capacity of 1020.4 mAh g−1 with sulfur loading even reaching 4.5 mg cm−2 after 200 cycles. The present work reveals an effective strategy for developing advanced Li–S batteries dual-functional electrodes.

In situ formed synaptic Zn@LiZn host derived from ZnO nanofiber decorated Zn foam for dendrite-free lithium metal anode

In situ formed synaptic Zn@LiZn host derived from ZnO nanofiber decorated Zn foam for dendrite-free lithium metal anode

High-safety, wide-temperature-range, low-external-pressure and dendrite-free lithium battery with sulfide solid electrolyte

Li metal is considered to be the most ideal anode due to its highest energy density, but traditional lithium-metal liquid-electrolyte battery system suffers from low Coulombic efficiency, repetitive SEI formation, Li dendrite growth, etc. Herein, a new battery configuration is proposed to exploit room-temperature liquid lithium solutions (Li-BP-Ether) as anodes and argyrodite sulfide as solid electrolyte. Such liquid lithium solutions can deliver high safety performance, excellent dendrite suppression capability, low redox potentials, and high conductivity of 12 mS cm−1 at room temperature. Moreover, sulfide solid electrolyte has the highest room-temperature ionic conductivity among all solid electrolytes and ideal mechanical ductility for fully compact layer simply by cold pressing. This battery configuration combines the advantages of these materials and can operate at neglectable external pressure (3 kPa) in a wide temperature range (−20∼50 °C). As a result, a high reversible discharge capacity (140.4 mAh g−1) and high efficiencies (99.7% Coulombic efficiency and >96% energy efficiency after ∼100 cycles) are achieved. Furthermore, this battery demonstrates the best cycle stability and the highest efficiency among all the liquid lithium solution battery systems using solid cathodes reported so far. Overall, this class of battery configuration may open up a promising route for high-energy-density, cost-effective and safe rechargeable lithium batteries.

Toward Dendrite-Free Metallic Lithium Anodes: From Structural Design to Optimal Electrochemical Diffusion Kinetics.

Lithium metal anodes are ideal for realizing high-energy-density batteries owing to their advantages, namely high capacity and low reduction potentials. However, the utilization of lithium anodes is restricted by the detrimental lithium dendrite formation, repeated formation and fracturing of the solid electrolyte interphase (SEI), and large volume expansion, resulting in severe "dead lithium" and subsequent short circuiting. Currently, the researches are principally focused on inhibition of dendrite formation toward extending and maintaining battery lifespans. Herein, we summarize the strategies employed in interfacial engineering and current-collector host designs as well as the emerging electrochemical catalytic methods for evolving-accelerating-ameliorating lithium ion/atom diffusion processes. First, strategies based on the fabrication of robust SEIs are reviewed from the aspects of compositional constituents including inorganic, organic, and hybrid SEI layers derived from electrolyte additives or artificial pretreatments. Second, the summary and discussion are presented for metallic and carbon-based three-dimensional current collectors serving as lithium hosts, including their functionality in decreasing local deposition current density and the effect of introducing lithiophilic sites. Third, we assess the recent advances in exploring alloy compounds and atomic metal catalysts to accelerate the lateral lithium ion/atom diffusion kinetics to average the spatial lithium distribution for smooth plating. Finally, the opportunities and challenges of metallic lithium anodes are presented, providing insights into the modulation of diffusion kinetics toward achieving dendrite-free lithium metal batteries.

In situ formation of a lithiophilic surface on 3D current collectors to regulate lithium nucleation and growth for dendrite-free lithium metal anodes

As the most promising anode material for lithium batteries, lithium metal faces rigorous challenges such as uncontrollable Li dendrite growth and safety risks, which hinder its practical applications. Herein, a uniform indium layer-decorated Ni foam is constructed as a three-dimensional current collector by electroplating to understand the effects of different substrates on the Li deposition morphology and electrochemical performance and to explore the mechanism for Li dendrite growth. The results indicate that an In3Li13 alloy layer is formed by an alloying reaction, which provides abundant nucleation sites for uniform Li deposition. Both simulations and experiments demonstrate that Li ions tend to deposit on the In3Li13 substrate rather than the Li nucleus, while they prefer to plate onto Li particles rather than onto the Ni substrate. Benefiting from the strong interaction, the In3Li13 substrate shows dispersed Li deposition behavior with a grain-like shape, which is different from the severe dendrite formation of bare Ni substrate. As a result, the In3Li13@NF electrode delivers an enhanced Coulombic efficiency of 97.4% for 300 cycles even under a severe cycling condition of 2 mA cm−2, and the Li-In3Li13@NF anode presents increased cycling stability in symmetric cells. Impressively, the Li-In3Li13@NF//LiFePO4 full cell delivers a remarkable capacity retention of 82.8% for 1000 cycles at 2 C. This work not only sheds light on the growth mechanism for Li dendrites but also provides a new strategy to develop high-energy density lithium metal batteries.

Conductive Iodine-Doped Red Phosphorus Enabled Dendrite-Free Lithium Deposition on MXene Matrix.

The highest theoretical capacity and lowest redox potential of lithium metal make lithium-based batteries the "holy grail" of the next-generation batteries. However, the uncontrollable dendrite growth and infinite volume change of lithium seriously hinder the real-world implementation of lithium-based batteries. Herein, a flexible MXene@iodine-doped red phosphorus (MXene@RP) paper with iodine-doped red phosphorous particles evenly distributed on the surface and interlayer of MXene matrix is designed by a simple vapor condensation reduction approach. The MXene@RP paper can be used as an efficient matrix to enable dendrite-free lithium deposition. On the one hand, the iodine doping alleviates the low conductivity shortcoming of red phosphorus, making it facilitate homogeneous lithium nucleation, thus promoting uniform lithium deposition and suppressing dendrite growth. On the other hand, the unique layered structure of conductive MXene paper provides ion transport channels and free spaces for lithium loading, alleviating the volume change induced structural damage. As a result, the MXene@RP paper with preloaded lithium exhibits long-term cycling stability. Particularly, a full cell based on Li-MXene@RP anode can maintain 81.4% of the initial capacity after 600 cycles at 4 C. The MXene@RP-based anode increases the potential applications of MXene and provides a guide for the design of dendrite-free lithium hosts.

Thermal Percolation of Antiperovskite Superionic Conductor into Porous MXene Scaffold for High-Capacity and Stable Lithium Metal Battery.

Lithium metal battery is considered an emerging energy storage technology due to its high theoretical capacity and low electrochemical potential. However, the practical exploitations of lithium metal batteries are not realized because of uncontrollable lithium deposition and severe dendrite formation. Herein, a thermal percolation strategy is developed to fabricate a dual-conductive framework using electronically conductive Ti3 C2 Tx MXene aerogels (MXAs) and Li2 OHCl antiperovskite superionic conductor. By melting Li2 OHCl at a low temperature, the molten antiperovskite phase can penetrate the MXA scaffold, resulting in percolative electron/ion pathways. Through density functional theory calculations and electrochemical characterizations, the hybridized lithiophilic (MXA)-lithiophobic (antiperovskite) interfaces can spatially guide the deposition of lithium metals and suppress the growth of lithium dendrites. The symmetric cell with MXA-antiperovskite electrodes exhibits superior cycling stability at high areal capacities of 4 mAh cm-2 over 1000 h. Moreover, the full cell with MXA-antiperovskite anode and high-loading LiFePO4 cathode demonstrates high energy and power densities (415.7Wh kgcell -1 and 231.0W kgcell -1 ) with ultralong lifespans. The thermal percolation of lithium superionic conductor into electronically conductive scaffolds promises an efficient strategy to fabricate dual-conductive electrodes, which benefits the development of dendrite-free lithium metal anodes with high energy/power densities.

A multifunctional constrained host towards dendrite-free lithium anode

Uncontrolled growth of Li dendrites, the huge volume change of anode as well as unstable solid-electrolyte interphase (SEI) hinder the safety application of high specific energy Li metal batteries (LMBs). Herein, a synergistic strategy is introduced to address the above issues via building a multifunctional constrained host of Ag2S/Ti3C2 film. Anchor the Ti3C2 nanosheets layers with Ag2S nanowires (Ag2S NWs) network to build a solid skeleton structure, which can provide sufficient void space, alleviate the collapse of the host structural during repeated Li plating/stripping. Furthermore, with the Li plating, Ag2S can be reduced to lithiophilic Ag, inducing the uniform Li nucleation and dendritic growth suppression, and the by-product Li2S in situ generation along the Ag2S NWs could strengthen the SEI. Consequently, the electrode of Li-Ag2S/Ti3C2 can operate stably for more than 1200 h at a current density of 0.5 mA cm–2 in the symmetric cell cycling test. The Li-Ag2S/Ti3C2||NCM811 coin cell exhibits high Coulombic efficiencies (CE) (97.94%) after 300 cycles at 1 C.

Lithium Atom Surface Diffusion and Delocalized Deposition Propelled by Atomic Metal Catalyst toward Ultrahigh-Capacity Dendrite-Free Lithium Anode.

Lithium metal anode possesses overwhelming capacity and low potential but suffers from dendrite growth and pulverization, causing short lifespan and low utilization. Here, a fundamental novel insight of using single-atomic catalyst (SAC) activators to boost lithium atom diffusion is proposed to realize delocalized deposition. By combining electronic microscopies, time-of-flight secondary ion mass spectrometry, theoretical simulations, and electrochemical analyses, we have unambiguously depicted that the SACs serve as kinetic activators in propelling the surface spreading and lateral redistribution of the lithium atoms for achieving dendrite-free plating morphology. Under the impressive capacity of 20 mA h cm-2, the Li modified with SAC-activator exhibits a low overpotential of ∼50 mV at 5 mA cm-2, a long lifespan of 900 h, and high Coulombic efficiencies during 150 cycles, much better than most literature reports. The so-coupled lithium-sulfur full battery delivers high cycling and rate performances, showing great promise toward the next-generation lithium metal batteries.

Fast Li+ transport pathways of quasi-solid-state electrolyte constructed by 3D MOF composite nanofibrous network for dendrite-free lithium metal battery

Lithium metal batteries with quasi-solid-state electrolytes are promising in the advanced energy storage system due to the high theoretical capacity and safety. Herein, a unique quasi-solid-state electrolyte (PUIE) containing 3D ion transport pathways based on UIO-66 has been constructed by a flexible process: electrospinning combined electrostatic spraying, followed by impregnation and roll press. In particular, UIO-66 with abundant Lewis acidic sites and channels enhances the ion transport and the restriction to anion in the electrolyte. The rationally designed PUIE-3 exhibits a high ionic conductivity of 1.08 mS/cm at 25 °C, a wide electrochemical window of 5.5 V, and a high Li+ transference number of 0.52. On the basis of the regulating effect of UIO-66, the growth of Li dendrites is significantly restrained and the electrolyte exhibits long-life electrochemical stability with Li anode during the Li plating/stripping. In consequence, lithium metal batteries loaded with PUIE-3 exhibit remarkable cycling and rate performance. Our results indicate that rational design polymer nanofiber/metal-organic framework membranes offer a new avenue for developing high performance quasi-solid-state electrolytes.

Modifying surface of Ni foam via hierarchical lithiophilic nanoarrays for stable lithium metal anodes

Lithium metal anode with high theoretical capacity has attracted lots of attention, but dendrite growth results in poor cyclic stability during the process of repeated plating/stripping. Herein, a scaffold constructed by surface growth of hierarchical lithiophilic acicular CoNiO2 on the porous Ni foam (NF@CoNiO2) is synthesized and used to construct three-dimensional (3D) host for lithium metal anode. The experimental results show that the lithium dendrite growth is effectively inhibited and satisfactory cycling performance is achieved. Benefiting from the stable lithiophilic sites, good conductivity from the NF, large porosity, and high strength 3D structure, the host enable Li||NF@CoNiO2@Li cells to deliver low hysteresis voltage (7.7 mV) and ultra-long cycling stability (more than 2800 h, 1400 cycles) at 1 mA cm−2 with a capacity of 1 mAh cm−2. The full cells configured the NF@CoNiO2@Li anode with LiFePO4 still display a reversible discharge capacity of 126.2 mAh g−1 after 140 cycles with a Coulombic efficiency of 92.5% at 1C. This work paves a feasible way to construct the lithiophilic skeleton for dendrite-free lithium metal anode.

Lamellar-structured anodes based on lithiophilic gradient enable dendrite-free lithium metal batteries with high capacity loading and fast-charging capability

Lithium (Li) metal batteries have attracted much attention due to extremely high energy density. However, safety concerns and limited lifetime associated with dendrite growth of Li anodes, especially at high capacity loadings and high rates, hamper their practical application. Here, we report the construction of lamellar-structured lithium host containing carbon nanotubes (CNTs), MXene nanosheets, and SnO2 nanoparticles via a simple step-by-step vacuum filtration method. The architecture is based on the lithiophilic gradient of each component, in which highly-lithiophilic SnO2 nanoparticles uniformly anchor on the lithiophilic MXene current collector, and lithiophobic CNTs act as the top protective layer. In this way, Li electrodeposition is spatially guided in a bottom-up mode free from dendrite growth. Consequently, the CNT/MXene/SnO2 scaffold accommodates a high capacity loading of 8 mAh cm−2 with only 4.6 % volume expansion. Furthermore, the Li@CNT/MXene/SnO2 electrode achieves fast-charging capability and long-term cycling stability in both symmetric cells (40 mA cm−2) and full cells (10C). This work demonstrates an efficient approach to construct dendrite-free anodes for durable and high-power lithium metal batteries.

Effect of electrochemical and mechanical properties of SEI on dendritic growth during lithium deposition on lithium metal electrode

Lithium metal represents the optimal candidate for the negative electrode, due to its high theoretical capacity (3860 mAh g−1) and low potential (−3.04 V compared to the standard hydrogen electrode). On the other hand, the major drawback of this technology is the formation of dendrites, which can cause thermal runaway and internal short-circuits, and are responsible for the limited lifetime of the cell. A dendrite-free lithium deposition is needed to improve this technology, thus, a deeper understanding of the phenomena and parameters that influence dendrite growth and formation is necessary. For the first time, the proposed model studies the influence of Solid Electrolyte Interphase (SEI) and its mechanical and electrochemical properties on the dendritic growth. Starting from the initial surface geometry and the electrochemical and mechanical properties of the components, the model can predict the conditions that favours dendritic growth and distinguish different surface morphologies depending on the applied current density. Moreover, the addition of the SEI mechanics allows the model to distinguish between tip-induced growth and root-induced growth, which is still not fully understood and has not been modelled yet.

Dynamic charge modulate lithium uniform plating functional composite anode for dendrite-free lithium metal batteries

Lithium metal is considered as the ‘sharp blade’ to break through the limitation on energy density of lithium batteries. However, uneven plating of lithium metal during charge/discharge process causes serious safety hazards. Here, a carbon-based 3D skeleton (CC@Co-NCNTs) with Co nanocrystals anchored N-containing carbon nanotubes (Co-NCNTs) was constructed to induce the uniform lithium plating towards dendrite-free lithium metal batteries. The Co-NCNTs in the skeleton exhibit enhanced lithophilicity, supplying abundant nucleation sites. Moreover, the ingenious hierarchical structure reconstructs the current density distribution, promoting the uniform lithium plating. Particularly, the electrons from the Co nanocrystals are transferred to the surface of Co-NCNTs, which offers a dynamic charge distribution on the surface of the skeleton along with the plating of lithium ions during the charge-discharge process, thus modulating uniform lithium plating on the Co-NCNTs skeleton. The above-mentioned mechanism is further verified by first-principle calculations and multi-physical field simulation. Thus, the CC@Co-NCNTs@Li symmetric cell presents a long-term cyclic stability (over 1300 h) at a high current density of 40 mA cm−2. The CC@Co-NCNTs@Li/LiFePO4 cell still delivers a discharge capacity of 135 mAh g−1 at 1 C after 500 cycles. This work provides new insights to the study of functional skeletons for dendrite-free lithium batteries.

Lithiophilic Ni3S2 layer decorated nickel foam (Ni3S2@Ni foam) with fast ion transfer kinetics for long-life lithium metal anodes

Lithium metal is regarded as the ultimate choice of anode material for high-energy batteries because of its ultrahigh theoretical capacity and ultralow reduction potential. Unfortunately, the infinite volume change and unavoidable dendrite growth encountered during repeated charge/discharge processes hamper its commercial applications. Herein, a lithiophilic Ni3S2 layer-decorated Ni foam (Ni3S2@Ni foam) is constructed as an advanced three-dimensional (3D) host for long-life lithium metal anodes. Benefiting from the 3D porous structure, the average current density is effectively reduced, and the volume change is accommodated. Remarkably, the Ni3S2@Ni foam with superior lithiophilicity decreases the energy barrier at the initial lithium nucleation stage, and the Li2S-enriched SEI layer formed after the initial activation process facilitates fast ion transfer kinetic, which promotes uniform Li+ surface diffusion and rapid lithium-ion transport, leading to dendrite-free lithium plating/stripping behavior and enhanced cycling performance. As a consequence, the Ni3S2@Ni foam delivers an average Coulombic efficiency (CE) of 98.3 % for 400 cycles at 1 mA cm−2, and a long-term life of over 1300 h with a low voltage hysteresis of ∼25 mV at 2 mA cm−2 is achieved in symmetric cell. Furthermore, full cells matching the LiFePO4 (LFP) cathode realize stable electrochemical performance over 400 cycles at 2C, indicating the application prospects for the Li-Ni3S2@Ni foam anode.

Lithiophilic onion-like carbon spheres as lithium metal uniform deposition host

Lithium metal is considered as a promising anode material for next-generation secondary batteries, owing to its high theoretical specific capacity (3860 mA h g−1). Nevertheless, the practical application of Li in lithium metal batteries (LMBs) is hampered by inhomogeneous Li deposition and irreversible “dead Li”, which lead to low coulombic efficiency (CE) and safe hazards. Designing unique lithiophilic structure is an efficient strategy to control Li uniformly plating /stripping. Here, we report the silver (Ag) nanoparticles coated with nitrogen-doped onion-like carbon microspheres (Ag@NCS) as a host to reduce the nucleation overpotential of Li for dendrite-free LBMs. The Ag@NCS were prepared by a simple one-step injection pyrolysis. The lithiophilic Ag is demonstrated to be priority selective deposition of Li in the carbon cage. Meanwhile, the onion-like structure benefits to uniform lithium nucleation and dendrite-free lithium during cycling. Impressively, we successfully captured lithium metal on different hosts at atomic scale, further proving that Ag@NCS can effectively and uniformly deposit Li. Besides, Ag@NCS show a superiorly electrochemical performance with a low nucleation overpotential (∼1 mV), high CE and stable cycling performance (over 400 cycles at 0.5 mA cm−2) compared to the Ag-free onion-like carbon in LMBs. Even under harsh conditions (1 mA cm−2, 4 mA h cm−2), Ag@NCS still present superior cycling stability for more than 150 cycles. Furthermore, a full cell composed of LiFePO4 cathode exhibits significantly improved voltage hysteresis with low voltage polarization. This work provides a new choice and route for the design and preparation of lithiophilic host materials.

Polysiloxane-Based Single-Ion Conducting Polymer Electrolyte for High-Performance Li‖NMC811 Batteries

The ongoing electrification of the transportation sector is triggering a continuous search for batteries with higher energy density. One approach to achieve this goal is the transition to lithium-metal anodes. However, the practical implementation brings about severe safety issues such as the dendritic deposition and growth of metallic lithium and the consequent risk of accidental short circuiting of the cell, resulting in a thermal runaway.1 Solid-state electrolytes such as polymers are considered a viable strategy to overcome this issue, especially single-ion conducting polymers, owing to the absence of the detrimental reversed cell polarization, the uniform Li+ flux, and frequently higher limiting current densities.2,3 In fact, the latter is of utmost importance for the fast charging of battery cells as well as the eventual power density. So far, however, the cycling performance at high dis-/charge rates and high current densities for battery cells comprising a polymer electrolyte remained little investigated and commonly non-satisfactory.Here, we report the development of a polysiloxane-based single-ion conducting polymer electrolyte (PSiOM) with a Li+ conductivity exceeding 10−4 S cm−1 at ambient temperature and excellent stability towards both lithium metal and high-energy LiNi0.8Co0.1Mn0.1O2 (NMC811) as the active material for the positive electrode. This new polymer electrolyte enables dendrite-free lithium deposition, thanks to the formation of a suitable electrode|electrolyte interface and interphase and the uniform Li+ flux. Moreover, PSiOM allows for an outstanding capacity retention of, e.g., 90% at 1C and 86% at 2C after 300 cycles and rapid charging and discharging at C rates as high as 5C. It is important to note that we used reasonable active material mass loadings for these tests (>7 mg cm-2), which means that the current densities applied were up to 7.20 mA cm−2 at 40 °C and 2.88 mA cm−2 at 20 °C. To the best of our knowledge, these current densities are among the highest reported so far for polymer-based electrolytes. References (1) Kalhoff, J.; Eshetu, G. G.; Bresser, D.; Passerini, S. Safer Electrolytes for Lithium-Ion Batteries: State of the Art and Perspectives. ChemSusChem 2015, 8 (13), 2154–2175.(2) Zhang, H.; Li, C.; Piszcz, M.; Coya, E.; Rojo, T.; Rodriguez-Martinez, L. M.; Armand, M.; Zhou, Z. Single Lithium-Ion Conducting Solid Polymer Electrolytes: Advances and Perspectives. Chemical Society Reviews 2017, 46 (3), 797–815.(3) Nguyen, H.-D.; Kim, G.-T.; Shi, J.; Paillard, E.; Judeinstein, P.; Lyonnard, S.; Bresser, D.; Iojoiu, C. Nanostructured Multi-Block Copolymer Single-Ion Conductors for Safer High-Performance Lithium Batteries. Energy & Environmental Science 2018, 11 (11), 3298–3309.

Enhanced Cyclability of Lithium Metal Anodes Enabled by Anti-aggregation of Lithiophilic Seeds.

Constructing 3D skeletons modified with lithiophilic seeds has proven effective in achieving dendrite-free lithium metal anodes. However, these lithiophilic seeds are mostly alloy- or conversion-type materials, and they tend to aggregate and redistribute during cycling, resulting in the failure of regulating Li deposition. Herein, we address this crucial but long-neglected issue by using intercalation-type lithiophilic seeds, which enable antiaggregation owing to their negligible volume expansion and high electrochemical stability against Li. To exemplify this, a 3D carbon-based host is built, in which ultrafine TiO2 seeds are uniformly embedded in nitrogen-doped hollow porous carbon spheres (N-HPCSs). The TiO2@N-HPCSs electrode exhibits superior Coulombic efficiency, high-rate capability, and long-term stability when evaluated as compertitive anodes for Li metal batteries. Furthermore, the superiority of intercalation-type seeds is comprehensively revealed through controlled experiments by various in situ/ex situ electron and optical microscopies, which highlights the excellent structural stability and lithiophilicity of TiO2 nanoseeds upon repeated cycling.

High-capacity, high-rate, and dendrite-free lithium metal anodes based on a 3D mixed electronic-ionic conductive and lithiophilic scaffold

Lithium metal anode possesses a high theoretical capacity and the lowest redox potential, while the severe growth of Li dendrite prevents its practical application. Herein, we prepared a structure of Li3P nanosheets and Ni nanoparticles decorated on Ni foam (NF) as a three-dimensional (3D) scaffold for dendrite-free Li metal anodes (Li-Li3P/Ni@Ni foam anodes, shortened as L-LPNNF) using a facile melting method. The Li3P nanosheets exhibit excellent Li-ion conductivity as well as superior lithiophilicity, and the 3D nickel scaffold provides sufficient electron conductivity and ensures structure stability. Therefore, symmetric cells assembled by L-LPNNF possess lowered voltage hysteresis and improved long cycle stability (a voltage hysteresis of 104.2 mV after 500 cycles at a high current density of 20 mA cm−2 with a high capacity of 10 mA h cm−2), compared with the cells assembled with Li foil or Li-NF anodes. Furthermore, the full cells with paired L-LPNNF anodes and commercial LiFePO4 cathodes suggest a specific capacity of 124.6 mA h g−1 and capacity retention of 90.8% after 180 cycles with the Coulombic efficiency (CE) of ∼100% at a current rate of 1 C. This work provides a potentially scalable option for preparing a mixed electronic-ionic conductive and lithiophilic scaffold for dendrite-free Li anodes at high current densities.

In situ formation of lithiophilic Li22Sn5 alloy and high Li-ion conductive Li2S/Li2Se via metal chalcogenide SnSSe for dendrite-free Li metal anodes

Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential. However, uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries. Herein, we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode. During the initial Li plating process, lithiophilic Li22Sn5 alloy and Li2S/Li2Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe. Density functional theory (DFT) calculation demonstrates that the formed Li2S/Li2Se achieves low Li diffusion energy barrier, ensuring rapid Li+ migration. Li22Sn5 alloy provides strong nucleation sites, promoting uniform Li nucleation. Furthermore, in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth. Consequently, SnSSe modified Cu foil delivered an ultralow nucleation overpotential, superior cycling stability with 450 cycles (Coulombic efficiency, >98%), and excellent plating/stripping behavior over 2200 h at 0.5 mA cm−2. Moreover, the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO4 (LFP) full cell, shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.