High-performance Li Metal Batteries Research Articles

A cation and anion dual-doping strategy in novel Li-rich Mn-based cathode materials for high-performance Li metal batteries

Lithium (Li)-rich Manganese (Mn)-based cathode materials are considered to be the most hopeful cathode materials for next-generation high-energy-density Li metal batteries. However, the rapid capacity fading and voltage decaying derived from phase transformation still hinder their practical application. Herein, we developed a cation/anion dual-doping strategy by synchronically incorporating Zr4+ cation and F− anion to boost the structural stability of the Li-rich Mn-based cathode. The strengthened transition metal-oxygen bonds raised by doping effect can inhibit the release of oxygen for enhanced electrochemical reversibility and mitigate the anisotropic lattice distortion to stabilize the layered structure. Meanwhile, dual doping strategy expands the lattice distance and increases oxygen vacancy formation energy, thereby improving ion diffusion kinetics and structural stability. As a result, the obtained cathode presents an excellent initial discharge capacity of 268.5 mAh g−1 and a prolonged cycle lifespan beyond 300 cycles. A stable cycling performance can be obtained under a high areal capacity of 5.17 mAh cm−2 with a low negative/positive electrode capacity ratio of 1.93. Our dual-doping strategy provides a valuable new idea for improving the structural stability and electrochemical properties of Li-rich Mn-based cathode materials, further promoting the development of high-energy-density Li metal batteries.

Engineering High-Performance Li Metal Batteries through Dual-Gradient Porous Cu-CuZn Host.

Porous copper (Cu) current collectors show promise in stabilizing Li metal anodes (LMAs). However, insufficient lithiophilicity of pure Cu and limited porosity in three-dimensional (3D) porous Cu structures led to an inefficient Li-Cu composite preparation and poor electrochemical performance of Li-Cu composite anodes. Herein, we propose a porous Cu-CuZn (DG-CCZ) host for Li composite anodes to tackle these issues. This architecture features a pore size distribution and lithiophilic-lithiophobic characteristics designed in a gradient distribution from the inside to the outside of the anode structure. This dual-gradient porous Cu-CuZn exhibits exceptional capillary wettability to molten Li and provides a high porosity of up to 66.05%. This design promotes preferential Li deposition in the interior of the porous structure during battery operation, effectively inhibiting Li dendrite formation. Consequently, all cell systems achieve significantly improved cycling stability, including Li half-cells, Li-Li symmetric cells, and Li-LFP full cells. When paired synergistically with the double-coated LiFePO4 cathode, the pouch cell configured with multiple electrodes demonstrates an impressive discharge capacity of 159.3 mAh g-1 at 1C. We believe this study can inspire the design of future 3D Li anodes with enhanced Li utilization efficiency and facilitate the development of future high-energy Li metal batteries.

Cation-Loaded Porous Mg2+-Zeolite Layer Direct Dendrite-Free Deposition toward Long-Life Lithium Metal Anodes.

Lithium metal, with ultrahigh theoretical specific capacity, is considered as an ideal anode material for the lithium-ion batteries. However, its practical application is severely plagued by the uncontrolled formation of dendritic Li. Here, a cation-loaded porous Mg2+-Zeolite layer is proposed to enable the dendrite-free deposition on the surface of Li metal anode. The skeleton channels of zeolite provide the low coordinated Li+-solvation groups, leading to the faster desolvation process at the interface. Meanwhile, anions-involved solvation sheath induces a stable, inorganic-rich SEI, contributing to the uniform Li+ flux through the interface. Furthermore, the co-deposition of sustained release Mg2+ realizes a new faster migration pathway, which proactively facilitates the uniform diffusion of Li on the lithium substrate. The synergistic modulation of these kinetic processes facilitates the homogeneous Li plating/stripping behavior. Based on this synergistic mechanism, the high-efficiency deposition with cyclic longevity exceeding 2100h is observed in the symmetric Li/Li cell with Mg2+-Zeolite modified anode at 1mA cm-2. The pouch cell matched with LiFePO4 cathode fulfills a capacity retention of 88.4% after 100 cycles at a severe current density of 1 C charge/discharge. This synergistic protective mechanism can give new guidance for realizing the safe and high-performance Li metal batteries.

Stabilizing Lithium-Metal Host Anodes by Covalently Binding MgF2 Nanodots to Honeycomb Carbon Nanofibers.

Constructing lithiophilic carbon hosts has been regarded as an effective strategy for inhibiting Li dendrite formation and mitigating the volume expansion of Li metal anodes. However, the limitation of lithiophilic carbon hosts by conventional surface decoration methods over long-term cycling hinders their practical application. In this work, a robust host composed of ultrafine MgF2 nanodots covalently bonded to honeycomb carbon nanofibers (MgF2/HCNFs) is created through an in situ solid-state reaction. The composite exhibits ultralight weight, excellent lithiophilicity, and structural stability, contributing to a significantly enhanced energy efficiency and lifespan of the battery. Specifically, the strong covalent bond not only prevents MgF2 nanodots from migrating and aggregating but also enhances the binding energy between Mg and Li during the molten Li infusion process. This allows for the effective and stable regulation of repeated Li plating/stripping. As a result, the MgF2/HCNF-Li electrode delivers a high Coulombic efficiency of 97% after 200 cycles, cycling stably for more than 2000 h. Furthermore, the full cells with a LiFePO4 cathode achieve a capacity retention of 85% after 500 cycles at 0.5C. This work provides a strategy to guide dendrite-free Li deposition patterns toward the development of high-performance Li metal batteries.

Adjusting Li+ Solvation Structures via Dipole-Dipole Interaction to Construct Inorganic-Rich Interphase for High-Performance Li Metal Batteries.

Practical applications of lithium metal batteries are limited by unstable solid electrolyte interphase (SEI) and uncontrollable dendrite Li deposition. Regulating the solvation structure of Li+ via modifying electrolyte components enables optimizing the structure of the SEI and realizing dendrite-free Li deposition. In this work, it is found that the ionic-dipole interactions between the electron-deficient B atoms in lithium oxalyldifluoro borate (LiDFOB) and the O atoms in the DME solvent molecule can weaken the interaction between the DME molecule and Li+, accelerating the desolvation of Li+. On this basis, the ionic-dipole interactions facilitate the entry of abundant anions into the inner solvation sheath of Li+, which promotes the formation of inorganic-rich SEI. In addition, the interaction between DFOB- and DME molecules reduces the highest occupied molecular orbital energy level of DME molecules in electrolytes, which improves the oxidative stability of the electrolytes system. As a result, the Li||Li cells in LiDFOB-containing electrolytes exhibit an excellent cyclability of over 1800h with a low overpotential of 18.2mV, and the Li||LiFePO4 full cells display a high-capacity retention of 93.4% after 100 cycles with a high Coulombic efficiency of 99.3%.

High-Performance Lithium Metal Batteries

The success of rechargeable lithium-ion batteries (LIBs) has brought evident convenience to human society, but state-of-the-art LIBs with a graphite anode are approaching their energy density limits. Li metal is considered the ultimate anode material due to its ultra-high theoretical specific capacity of 3860 mAh g-1, which is more than 10 times higher than lithiated graphite. Nonetheless, Li metal anode suffers from poor safety and low cycling efficiency due to its high reactivity. Electrolytes that work with Li anode should possess excellent stability against Li metal or form a highly passivating interface. It is also critical to control the amount of Li in the cell, preferably having no excess Li at the anode side. In this talk next-generation solid state and hybrid electrolytes based on Li-stuffed garnets that enable high-performance Li metal batteries will be discussed.

Self-supported 3D current collector modified with in-situ formed lithiophilic [Cu(NH3)2]Cl for high-performance Li-metal batteries

Li-metal batteries (LMBs) are regarded as some of the most promising energy storage systems owing to their superior theoretical specific capacity and lowest electrochemical potential. However, the application of LMBs has been severely hindered by the uncontrollable dendrite growth and volume expansion of metal anodes during Li plating. Herein, we construct a three-dimensional (3D) porous CuZn current collector decorated with a lithiophilic [Cu(NH3)2]Cl compound (3D 1H3N), in which [Cu(NH3)2]Cl offers nucleation sites and guides fast Li+ deposition in the pores and tunnels. The 3D framework accommodates volume expansion and disperses deposition current. Together, these two functions contribute to low-barrier and dendrite-free Li plating/stripping with enhanced Coulombic efficiency (CE) and excellent stability. The half-cell utilizing the as-fabricated 3D 1H3N current collector exhibited a CE of 98 % for over 270 cycles at 0.5 mA·cm–2 and 97 % for over 220 cycles at 1 mA·cm–2. The Li@3D 1H3N anode stabilized over 270 cycles (1100 h) at 0.5C in symmetric cells and delivered a capacity retention of 92.5 % after 450 cycles at 1C (1C = 170 mAh·g–1) in full cells. This study sheds light on the multifunction modification of self-supported anode current collectors for advanced LMBs to promote their practical application.

Uniform Li-metal growth on renewable lignin with lithiophilic functional groups derived from wood for high-performance Li-metal batteries

Lithium metal batteries (LMBs) are promising energy storage devices with high energy density owing to their high theoretical capacity (3860 mAh g−1) and low reduction potential of lithium (Li)-metal anodes. However, their practical application is limited by poor Coulombic efficiency (CE) and safety issues due to Li dendrite growth during Li plating/stripping. Herein, a three-dimensional (3D) structure of lignin with a lithiophilic functional group derived from waste wood is suggested as an additional functional layer of LMBs, i.e., a lignosulfonic acid sodium salt (LASS) with a negatively charged sulfonate group (SO3−) in its chemical structure. The SO3− group enhances the Li-ion (Li+) affinity and enables Li+-flux control, supplying homogeneous Li growth sites. It induces stable electrochemical dendrite-free Li growth. Consequently, in the LASS-Cu||Li half-cell, a high CE of 96.7 % at 210 cycles and stable operation is achieved without a short circuit and, symmetric-cell with LASS layers shows stable cycling over 2000 h. Moreover, full-cells with LiFePO4 (LFP) and LiNi0.8Co0.1Mn0.1O2 (NCM 811) cathodes exhibit enhanced electrochemical performance. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) reveal that the LASS layer suppressed dendritic Li growth and stimulated densely packed Li growth. This work suggests an effective strategy for improving the performance of LMBs using renewable lignin materials.

Electronegative graphene film based interface-chemistry regulation for stable lithium metal batteries

To achieve practical application of lithium (Li) metal anodes for high-energy–density batteries, the primary challenges of the inhomogeneous solid electrolyte interphase (SEI) and irregular Li electrochemical stripping/depositing behaviors should been surmounted. So as to homogenize Li+ distribution and stabilize the SEI layer, herein, we reported a partially reduced graphene oxide (PrGO) film with a manageable electronegativity as an ideal Li host to construct composite electrode (PrGO@Li). The fabricated PrGO with tunable oxygen amount and negatively charge can achieve controllable Li capacity avoiding excess Li. More importantly, the electronegative PrGO film matrix can cause an electrostatic force and thereby regulate the Li+ distribution pattern and diffusion kinetics, which induces a homogeneous and stable LiF-rich SEI and highly conformal Li+ stripping/deposition behaviors without Li dendrites. As a result, the optimal PrGO@Li electrode delivers long-term reversible Li+ stripping/depositing processes with an extremely low overpotential (7 mV) after 2000 h cycling at 20 mA cm−2 and 10 mAh cm−2. Moreover, the full battery based on this anode paired with LiFePO4 cathode exhibits outstanding cycling stability, high rate capacity and excellent flexibility characters. Meanwhile, the controllable PrGO films can also be loading with sulfur as cathodes for satisfactory Li/sulfur batteries. This research deeply analyzes the intermediation mechanism between the graphene host and Li+ on the electrochemical behaviors, and offers universal guidance for the development of high-performance Li-metal batteries.

Towards high performance Li metal batteries: Surface functionalized graphene separator with improved electrochemical kinetics and stability

Lithium (Li) metal is a promising anode for next-generation batteries owing to its ultrahigh theoretical capacity (3,860 mAh g−1) and the lowest reduction potential (−3.04 vs SHE at RT). However, the development of Li-metal batteries (LMBs) is still in the research stage due to the inherent problems related to the growth of Li dendrites and unlimited volume change in Li metal. Among diverse approaches, the introduction of functional separators is regarded as an effective strategy for improving the safety and electrochemical performance of LMBs. Herein, we deposited two different graphene layers onto the separators to explore the influence of surface functionalized graphene layer on the electrochemical performance and cycle stability of LMBs. When a surface functionalized graphene separator (SFGS) was used in the LMBs, it exhibited superior electrolyte wettability than a graphene separator (GS), contributing to the improved ionic conductivity and homogeneous Li-ion flux. Due to the improved electrochemical kinetics and reversible electrochemical reactions, Li/Cu cells with the SFGS exhibited the most stable cycle performance with a high Coulombic efficiency of 98 % over 200 cycles compared with other Li/Cu cells. Our strategy would resolve many issues related to the poor electrochemical reversibility of Li-metal anodes and advance the development of practical surface-modified separators for high-performance LMBs.

Fine-tuned molecular design toward a stable solid electrolyte interphase on a lithium metal anode from in silico simulation

Electrolyte engineering has emerged as a promising approach for enhancing the performance of lithium (Li) metal batteries, with recent advancements in novel electrolytes contributing to improved battery performance. Nevertheless, the intricate electrochemical interface poses significant challenges for experimental studies, resulting in a limited fundamental understanding of interface phenomena. To address this issue, we utilize hybrid ab initio and reactive molecular dynamics (HAIR) simulations to examine the solid electrolyte interphase (SEI) formation process and chemical composition at the atomic level in a series of fluorinated pseudo-localized high-concentration electrolytes (LHCEs). Our detailed analysis uncovers that ionic conductivity, the abundance of LiF, and oligomer length are three pivotal factors influencing cell performance. The simulations not only corroborate the –CF2- fluorinated backbone scheme, aligning with experimental findings but also reveal new opportunities for enhancing performance through the introduction of –CHF– moieties based on the concept of incremental design. Consequently, we propose a novel solvent molecule, fluorinated 1,2,3,4,5,6-hexa-1,6-dimethoxylhexane (FHDH), and demonstrate that FHDH maintains desirable physicochemical properties and high F concentration while exhibiting superior SEI physicochemical properties in terms of ionic conductivity, relative amount of LiF, and long-chain oligomers. Our findings offer a rational explanation for experimental design strategies and suggest further electrolyte optimization based on these insights, paving the way for the development of high-performance Li metal batteries.

(Invited) High-Performance Lithium Metal Batteries

The success of rechargeable lithium-ion batteries (LIBs) has brought evident convenience to human society, but state-of-the-art LIBs with a carbon anode are approaching their energy density limits. Li metal is considered the ultimate anode material due to its ultra-high theoretical specific capacity of 3860 mAh g-1, which is more than 10 times higher than lithiated graphite. Nonetheless, Li anode suffers from poor safety and low cycling efficiency due to its high reactivity. Electrolytes that work with Li anode should possess excellent stability against Li metal or form a highly passivating interface. It is also critical to control the amount of Li in the cell, preferably having no excess Li at the anode side.1 In this presentation, next-generation electrolytes that enable such types of high-performance Li metal batteries will be discussed, including advanced liquid electrolytes,2 garnet-type ceramic electrolytes3–5 and hybrid electrolytes.6,7 References C. Zhou, A. J. Samson, M. A. Garakani, and V. Thangadurai, J. Electrochem. Soc., 168, 060532 (2021).C. Zhou et al., Energy Storage Mater., 42, 295–306 (2021) https://doi.org/10.1016/j.ensm.2021.07.043.S. P. Kammampata, R. H. Basappa, T. Ito, H. Yamada, and V. Thangadurai, ACS Appl. Energy Mater., 2, 1765–1773 (2019).S. P. Kammampata, H. Yamada, T. Ito, R. Paul, and V. Thangadurai, J. Mater. Chem. A, 8, 2581–2590 (2020).C. Zhou, A. J. Samson, K. Hofstetter, and V. Thangadurai, Sustain. Energy Fuels, 2, 2165–2170 (2018).S. Bag, C. Zhou, P. J. Kim, V. G. Pol, and V. Thangadurai, Energy Storage Mater., 24, 198–207 (2019) https://doi.org/10.1016/j.ensm.2019.08.019.C. Zhou, S. Bag, T. He, B. Lv, and V. Thangadurai, Appl. Mater. Today, 19, 100585 (2020) https://doi.org/10.1016/j.apmt.2020.100585.

Unique Tridentate Coordination Tailored Solvation Sheath Toward Highly Stable Lithium Metal Batteries.

Electrolyte optimization by solvent molecule design is recognized as an effective approach for stabilizing lithium (Li) metal batteries. However, the coordination pattern of Li ions(Li+ ) with solvent molecules is sparsely considered. Here, an electrolyte design strategy is reported based on bi/tridentate chelation of Li+ and solvent to tune the solvation structure. As a proof of concept, a novel solvent with multi-oxygen coordination sites is demonstrated to facilitate the formation of an anion-aggregated solvation shell, enhancing the interfacial stability and de-solvation kinetics. As a result, the as-developed electrolyte exhibits ultra-stable cycling over 1400h in symmetric cells with 50µm-thin Li foils. When paired with high-loading LiFePO4 , full cells maintain 92% capacity over 500 cycles and deliver improved electrochemical performances over a wide temperature range from -10 to 60°C. Furthermore, the concept is validated in a pouch cell (570mAh), achieving a capacity retention of 99.5% after 100 cycles. This brand-new insight on electrolyte engineering provides guidelines for practical high-performance Li metal batteries.

High Mass Loading of Edge-Exposed Cu3P Nanocrystal in 3D Freestanding Matrix Regulating Lithiophilic Sites for High-Performance Lithium Metal Anode.

Lithium (Li) dendrites and volume expansion during repeated Li plating and stripping processes are the major obstacles to the development of advanced Li metal batteries. Li nucleation and dendrite growth can be controlled and inhibited spatially by using 3-dimensional (3D) hosts together with efficient lithiophilic materials. To realize next-generation Li-metal batteries, it is critical to effectively regulate the surface structure of the lithiophilic crystals. Herein, exposed-edged Cu3P faceted nanoparticles anchored along the interlaced carbon nanofibers (ECP@CNF) are developed as a highly efficient 3D Li host. Through the 3D interlaced rigid carbon skeleton, volume expansion can be accommodated. The (300)-dominant edged crystal facets of Cu3P with abundant exposed P3- sites not only exhibit strong micro-structural Li affinity but also have relatively high charge transference to nucleate uniformly and effectively, resulting in reduced polarization. Consequently, under a high current density of 10 mA cm-2 with a high discharge of depth (60%), ECP@CNF/Li symmetric cells demonstrate outstanding cycling stability for 500 h with a small voltage hysteresis of 32.8 mV. Notably, the ECP@CNF/Li∥LiFePO4 full cell exhibits a more stable cycling performance for 650 cycles under a high rate of 1 C, with capacity retention up to 92% (N/P = 10, 4.7 mg cm-2 LiFePO4). Even under a limit Li (3.4 mA h) with an N/P ratio of 2 (8.9 mg cm-2 LiFePO4), ECP@CNF/Li∥LiFePO4 full cell can also demonstrate excellent reversibility and stable cycling performance with higher utilization of Li. This work provides an insight view into constructing high-performance Li-metal batteries under more strict conditions.

Developing multifunctional amide additive by rational molecular design for high-performance Li metal batteries

Rechargeable lithium batteries based on lithium metal anodes and high-nickel cathodes have unparalleled advantages in energy density. However, the massive growth of lithium dendrites and the rapid degradation of high-nickel ternary oxides in commercial electrolyte have greatly hindered their application. To circumvent this issue, we design a series of analogs as electrolyte additives by adopting acetyls as connecting units to splice multiple functional groups. Among these additives, N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) stands out due to the rational molecular configuration and the synergistic complementarity of amide, trifluoromethyl and trimethylsilyl groups. The cycling reversibility of the lithium metal anode (1050 h at 1 mA cm−1 to 1 mAh cm−1) and the capacity retention of the LiNi0.9Co0.05Mn0.05O2 cathode (85.9 % at 3–4.3 V after 300 cycles) in MSTFA modified carbonate electrolyte are tremendously enhanced. In addition, the safety of the battery and the tolerance to harsh working conditions (high & low temperature, high-voltage) are also ameliorated. This work sheds light on the relationship between structure and activity of molecules as well as provides a novel idea for modular design of additives.

Functional Separator Enabled by Covalent Organic Frameworks for High-Performance Li Metal Batteries.

Uncontrolled ion transport and susceptible SEI films are the key factors that induce lithium dendrite growth, which hinders the development of lithium metal batteries (LMBs). Herein, a TpPa-2SO3 H covalent organic framework (COF) nanosheet adhered cellulose nanofibers (CNF) on the polypropylene separator (COF@PP) is successfully designed as a battery separator to respond to the aforementioned issues. The COF@PP displays dual-functional characteristics with the aligned nanochannels and abundant functional groups of COFs, which can simultaneously modulate ion transport and SEI film components to build robust lithium metal anodes. The Li//COF@PP//Li symmetric cell exhibits stable cycling over 800h with low ion diffusion activation energy and fast lithium ion transport kinetics, which effectively suppresses the dendrite growth and improves the stability of Li+ plating/stripping. Moreover, The LiFePO4//Li cells with COF@PP separator deliver a high discharge capacity of 109.6 mAh g-1 even at a high current density of 3 C. And it exhibits excellent cycle stability and high capacity retention due to the robust LiF-rich SEI film induced by COFs. This COFs-based dual-functional separator promotes the practical application of lithium metal batteries.

Halloysite nanotubes modified poly(vinylidenefluoride-co-hexafluoropropylene)-based polymer-in-salt electrolyte to achieve high-performance Li metal batteries

Solid-state Li metal batteries (SSLMBs) are one of the most promising energy storage devices, as they offer high energy density and improved safety compared to conventional Li-ion batteries. However, the large-scale application of SSLMBs at room temperature is restricted by the main challenges such as low ionic conductivity and poor cyclic performance. Herein, a composed polymer-in-salt electrolyte (CPISE) is fabricated, which is composed of polyvinylidene vinylidene hexafluoropropene (PVDF-HFP) and high-concentration Li bis(trifluoromethanesulphonyl)imide (LiTFSI), reinforced with natural halloysite nanotubes (HNTs). The High concentration of LiTFSI and introduced HNTs synergized with PVDF-HFP to provide more various Li+ transport pathways. Additionally, the backbones of the uniform dispersion of HNTs in the CPISE effectively boosts the physicochemical nature of the CPISE. As a result, the prepared CPISE achieves excellent mechanical strength, high ionic conductivity (1.23*10-3 S cm−1) and high Li+ transference number (0.57) at room temperature. Consequently, in existence of the CPISE, the Li symmetric cell cycles stably beyond 800 h at 0.15 mA cm−2 and the LiFePO4/Li cell displays impressive cyclic performance with capacity retention of 79% after 1000 cycles at 30 °C. Furthermore, the superiority and the functional mechanism of the CPISE are discovered in detail. This work provides a promising strategy for the development of high-performance SSMLBs at room temperature.

Mixed Ion/Electron Conductive Li3N-Mo Interphase Enabling Stable and Ultrahigh-Rate Lithium Metal Anodes.

Lithium (Li) metal is a promising anode for high-energy-density batteries; however, its practical viability is hampered by the unstable metal Li-electrolyte interface and Li dendrite growth. Herein, a mixed ion/electron conductive Li3N-Mo protective interphase with high mechanical stability is designed and demonstrated to stabilize the Li-electrolyte interface for a dendrite-free and ultrahigh-current-density metallic Li anode. The Li3N-Mo interphase is simultaneously formed and homogeneously distributed on the Li metal surface by the surface reaction between molten Li and MoN nanosheets powder. The highly ion-conductive Li3N and abundant Li3N/Mo grain boundaries facilitate fast Li-ion diffusion, while the electrochemically inert metal Mo cluster in the mosaic structure of Li3N-Mo inhibits the long-range crystallinity and regulates the Li-ion flux, further promoting the rate capability of the Li anode. The Li3N-Mo/Li electrode has a stable Li-electrolyte interface as manifested by a low Li overpotential of 12 mV and outstanding plating/stripping cyclability for over 3200 h at 1 mA cm-2. Moreover, the Li3N-Mo/Li anode inhibits Li dendrite formation and exhibits a long cycling life of 840 h even at 30 mA cm-2. The full cell assembled with LiFePO4 cathode exhibits stable cycling performance with 87.9% capacity retention for 200 cycles at 1C (1C = 170 mA g-1) as well as high rate capability of 83.7 mAh g-1 at 3C. The concept of constructing a mixed ion/electron conductive interphase to stabilize the Li-electrolyte interface for high-rate and dendrite-free Li metal anodes offers a viable strategy to develop high-performance Li-metal batteries.

Self-shutdown function and uniform Li-ion flux enabled by a double-layered polymer electrolyte for high-performance Li metal batteries

Self-shutdown function and uniform Li-ion flux enabled by a double-layered polymer electrolyte for high-performance Li metal batteries

Uniform lithium deposition enabled by a carbon nanotubes framework modified with nanosized ZIF-8 particles for dendrite-free lithium metal anode

Lithium (Li) metal is considered as an exciting anode candidate for next-generation high-performance Li metal batteries because of its high theoretical capacity and lowest redox potential. Unfortunately, unavoidable challenges consisting of dendritic behavior and volume change obstruct its widely commercial application. Here, a three-dimensional (3D) oxidized carbon nanotubes framework modified with lithiophilic nano-ZIF-8 particles (CNTs@ZIF-8) has been fabricated by a simple solution method as the collector for uniform Li deposition. The polar groups from oxidized CNTs and ZIF-8 nanoparticles provide adhesion sites for Li nucleation. Meanwhile, the nano-ZIF-8 particles with large specific surface area enhance electrolyte absorption, attracting electrolyte to the CNTs surface. The composite structure with nanoscale surface modification can guide homogeneous Li plating and restrain Li dendrites growth. As a consequence, the symmetrical cell of CNTs@ZIF-8/Cu–Li reveals a stable cycle time (over 1500 h) with a hysteresis voltage (9 mV) at 1 mA cm−2. The full cell assembled by LiFePO4 (LFP) cathode and CNTs@ZIF-8/Cu–Li anode achieves outstanding rate and cycle performance which is superior to the CNTs/Cu–Li‖LFP, demonstrating that the CNTs@ZIF-8 is prospective for practical applications.