High-performance Lithium Metal Batteries Research Articles

In-situ construction of high-temperature-resistant 3D composite polymer electrolyte membranes towards high-performance all-solid-state lithium metal batteries

Enabling solid polymer electrolytes (SPEs) with enhanced electrochemical properties and high-temperature-resistance is highly desirable for developing high-performance lithium metal batteries (LMBs) with high-safety. In this contribution, single-ion conducting polymers and SiO2 particles, as advanced fillers, are in-situ cross-linked in poly(ethylene oxide) (PEO) based SPEs to form three-dimensional (3D) cross-linking inorganic/organic composite SPEs. Benefiting from the hydrogen bond interaction between the additives and PEO chains, the crystallinity of PEO polymers in the resultant SPEs is greatly decreased, giving rise to high conductivity (3.3 × 10−4 S cm−1) and lithium ion transference number (0.60) at 60 °C. The Li/Li symmetrical cells with the composite SPEs can be run stably more than 400 h at 60 °C and 550 h at 120 °C under 0.1 mA cm−2, respectively. Remarkably, the favorable thermal stability of composite SPEs leads to safer solid-state LMBs operating at the high temperature up to 120 °C, where it reaches an outstanding rate performance up to 4C and displays impressive cycling performances with 89.9% retention over 110 cycles at 1C. This work offers tremendous potential in the practical application of dendrite-free and high-performance LMBs.

A multifunctional subassembly of carbon nanotube paper for stable lithium metal anodes

Uncontrolled lithium growth and the consequent interfacial reaction are obstacles to the practical application of lithium metal anode. Here, a multifunctional subassembly of carbon nanotube paper grafted with a thin layer of LiNO3 (LNO@CP) is proposed. According to the results of experiments and theory calculation, the nucleation sites are enriched and the nuclei are tailored into spherical shape on LNO@CP. Consequently, the Li plating gradually fills the void of LNO@CP and then grows outward uniformly, resulting in an increased Li reversibility and a stable solid electrolyte interphase layer. The LNO@CP covering the Li backup source works as a protective layer to defense the electrolyte corrosion effectively. The lithium metal battery with this multifunctional subassembly delivers a remarkable capacity retention of 81.2% after 500 cycles. This work emphasizes that the a protective layer such as LNO@CP is crucial to the high performance lithium metal battery.

Visualizing the failure of solid electrolyte under GPa-level interface stress induced by lithium eruption

Solid electrolytes hold the promise for enabling high-performance lithium (Li) metal batteries, but suffer from Li-filament penetration issues. The mechanism of this rate-dependent failure, especially the impact of the electrochemo-mechanical attack from Li deposition, remains elusive. Herein, we reveal the Li deposition dynamics and associated failure mechanism of solid electrolyte by visualizing the Li|Li7La3Zr2O12 (LLZO) interface evolution via in situ transmission electron microscopy (TEM). Under a strong mechanical constraint and low charging rate, the Li-deposition-induced stress enables the single-crystal Li to laterally expand on LLZO. However, upon Li “eruption”, the rapidly built-up local stress, reaching at least GPa level, can even crack single-crystal LLZO particles without apparent defects. In comparison, Li vertical growth by weakening the mechanical constraint can boost the local current density up to A·cm−2 level without damaging LLZO. Our results demonstrate that the crack initiation at the Li|LLZO interface depends strongly on not only the local current density but also the way and efficiency of mass/stress release. Finally, potential strategies enabling fast Li transport and stress relaxation at the interface are proposed for promoting the rate capability of solid electrolytes.

Novel Urea-Based Molecule Functioning as a Solid Electrolyte Interphase Enabler and LiPF6 Decomposition Inhibitor for Fast-Charging Lithium Metal Batteries.

The practical application of lithium metal batteries is impeded by the growth of dendrites and decomposition of electrolytes especially at high temperature in normal carbonate-based electrolytes. Herein, a novel urea-based molecule, 1,3-dimethyl-2-imidazolidinone (DMI), with a high donor number is proposed, which exhibits an extraordinary solubility of LiNO3 of over 5 M. As a result, a sufficient amount of LiNO3 is readily introduced into the carbonate electrolytes with DMI as an additive, and an average coulombic efficiency of 99.1% for lithium plating/stripping is achieved due to a stable solid electrolyte interphase (SEI) rich in inorganic-rich lithium salts. The Li||Li symmetric cell achieves a stable operation for over 2500 h at 0.5 mA cm-2 and 1 mAh cm-2, and a granular shape of deposited Li metal is still preserved even at a high current density of 10 mA cm-2. Besides, the decomposition of LiPF6 is inhibited benefiting from its enhanced dissociation after the addition of DMI/LiNO3 and DMI's function as a PF5 scavenger. Consequently, the Li||LiFePO4 cell succeeds to achieve an excellent capacity retention of 95.6% after 2200 cycles at a high rate of 5C, and a stable operation is realized at a high temperature of 60 °C even under harsh conditions (45 μm ultrathin Li and ∼1.5 mAh cm-2 LiFePO4). This work enriches the solvents and additives pool for stable and high-performance lithium metal batteries and will shed light on future developments of advanced battery electrolytes.

High-performance PEO-based solid-state LiCoO2 lithium metal battery enabled by poly(acrylic acid) artificial cathode electrolyte interface

Solid-state lithium metal batteries (SSBs) have attracted ever-increasing attention because of the enhanced energy density and safety. However, the solid-solid contact resistance and interfacial stability pose a huge challenge in the practical application of SSBs. In this work, poly(acrylic acid) (PAA) is coated onto the LiCoO2 (LCO) cathode surface via a simple drop-casting method in SSB employing poly(ethylene oxide) (PEO)-based electrolyte to construct an artificial cathode electrolyte interface (ACEI). It proves that the ACEI can not only form percolating Li+ pathways across the electrode, but also protect the PEO electrolyte from being oxidized. Besides, Li+/H+ exchange reaction is found between LCO and PAA during the initial cycles, which further promote the interfacial ion transport and lead to enhanced battery kinetics. Galvanostatic charge/discharge and electrochemical impedance spectroscopy test indicate that the 0.5% PAA-treated LCO presents superior capacity retention of 93.3% after 120 cycles at 0.4 C when it works at 60 °C. PAA-LCO|PEO|Li pouch cells are also prepared and a reversible capacity of 145 mAh/g after 50 cycles at 0.1 C is achieved, which further demonstrates the feasibility of this strategy.

Oxygen vacancies with localized electrons direct a functionalized separator toward dendrite-free and high loading LiFePO4 for lithium metal batteries

The pursuit of high energy density has promoted the development of high-performance lithium metal batteries (LMBs). However, the underestimated but non-negligible dendrites of Li anode have been observed to shorten battery lifespan. Herein, a composite separator (TiO2−x@PP), in which TiO2 with electron-localized oxygen vacancies (TiO2−x) is coated on a commercial PP separator, is fabricated to homogenize lithium ion transport and stabilize the lithium anode interface. With the utilization of TiO2−x@PP separators, the symmetric lithium metal battery displays enhanced cycle stability over 800 h under a high current density of 8 mA cm−2. Moreover, the LMBs assembled with high-loading LiFePO4 (9.24 mg cm−2) deliver a stable cycling performance over 900 cycles at a rate of 0.5 C. Comprehensive theoretical studies based on density functional theory (DFT) further unveil the mechanism. The favorable TiO2−x is beneficial for facilitating fast Li+ migration and impeding anions transfer. In addressing the Li dendrite issues, the use of TiO2−x@PP separator potentially provides a facile and attractive strategy for designing well-performing LMBs, which are expected to meet the application requirements of rechargeable batteries.

Multiple ionic conduction highways and good interfacial stability of ionic liquid-encapsulated cross-linked polymer electrolytes for lithium metal batteries

PEO-based electrolytes are promising for solid-state lithium metal batteries, but their low ionic conductivity and unstable interfacial compatibility with electrodes are the bottlenecks restricting their further applications. Herein, a unique ionic liquid (Pyr14TFSI)-encapsulated cross-linked polymer electrolyte with abundant ether–oxygen repeat units (C-SPE-IL) is proposed and prepared through an in-situ thermal polymerization process. The Pyr14+ cations of ionic liquid present a stronger affinity towards ether–oxygen groups by means of tight coordinated interactions, which promotes ionic liquid encapsulated uniformly in the polymer matrix to release more mobile Li ions into ionic liquid and create multiple ionic conduction highways in both ionic liquid and polymer matrix. The C-SPE-IL shows a much higher ionic conductivity of 3.98 × 10−4 S/cm at 30 °C. Moreover, tight interfaces with LiF– and Li3N– rich components between C-SPE-IL and Li anode are constructed to ensure effective suppression of lithium dendrites during cycling. The LiFePO4/Li batteries using C-SPE-IL present stable cycling performances at both 35 °C and 60 °C. This work provides a facile and accessible approach to design novel SPE with both ionic conduction highways and good interfacial stability for high-performance solid-state lithium metal batteries.

(Invited) Advanced Electrolytes for 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.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.

Bifunctional Solid-State Copolymer Electrolyte with Stabilized Interphase for High-Performance Lithium Metal Battery in a Wide Temperature Range.

Solid-state polymer electrolytes (SPEs) are expected to guarantee safe and durable operations of lithium metal batteries (LMBs). Herein, inspired by the salutary poly(vinyl ethylene carbonate) (PVEC) component in the solid electrolyte interphase, cross-linking vinyl ethylene carbonate and ionic liquid copolymers were synthesized by in-situ polymerization to serve as polymer electrolyte for LMBs. On one hand, due to rich ester bonds of PVEC, Li+ could transfer by coupling/decoupling with oxygen atoms. On the other hand, the imidazole ring of ionic liquid could facilitate the dissociation of lithium salt to promote the free movement of Li+ . The bifunctional component synergistically increased the ionic conductivity of the SPE to 1.97×10-4 S cm-1 at 25 °C. Meanwhile, it also showed a wide electrochemical window, superior mechanical properties, outstanding non-combustibility, and excellent interfacial compatibility. The bifunctional copolymer-based LiFePO4 batteries could normally operate at 0 to 60 °C, making them a promising candidate for wide-temperature-rang LMBs.

A Polymerized‐Ionic‐Liquid‐Based Polymer Electrolyte with High Oxidative Stability for 4 and 5 V Class Solid‐State Lithium Metal Batteries (Adv. Energy Mater. 27/2022)

Polymer Electrolytes In article number 2200412, Chengyin Fu and co-workers develop a nonflammable polymer solid electrolyte, based on a low-cost polymerized ionic liquid, with a high room-temperature ionic conductivity of 0.8 mS cm−1 and a high oxidative stability > 5.0 V vs Li+/Li. The electrolyte enables high-performance solid-state lithium metal batteries with a high-energy uncoated LiNi0.8Mn0.1Co0.1O2 cathode and a high-voltage LiMn1.5Ni0.5O4 cathode at room temperature.

Fluorinated graphene as a dual-functional anode to achieve dendrite-free and high-performance lithium metal batteries

Lithium metal batteries (LMBs) are suffering from dendrite growth and a low coulombic efficiency (CE) during cycling. The use of the 3D structured current collector as lithium host and an artificial solid-electrolyte interphase (ASEI) layer were both regarded as efficient methods to improve the anode performance. However, the reliable binder-free coating requires a controllable species (LiF) and conformability, which is still challenging. Herein, we propose a dual-functional coating layer that played the role of both lithium deposition host and the ASEI by predepositing fluorinated electrochemically exfoliated graphene (F-ECG) as a modifier on a working electrode in LMBs. With the ultra-strong interface and interlayer adhesion, the as-prepared coating layer could successfully prevent not only the peeling-off issue that usually happened in coating layers of carbon-based materials but also the expansion during charge/discharge cycles. Also, the LiF-rich film is constructed through the reaction of Li ions with the F species from F-ECG, exhibiting homogeneous Li plating/stripping without notable dendrite formation. As a result, the half-cell possesses a low nucleation overpotential (18 mV) and high stability for over 100 cycles with an average CE of 98.3%. The polarization profile shows remarkable performance for up to 250 h. Additionally, a full-cell LMB (NMC||F-ECG) is demonstrated to achieve excellent capacity retention of up to 72% after 70 cycles. The LiF-rich dual-functional coating layer based on F-ECG as a modifier successfully improves the long-term stability of working electrodes, paving the way to realizing potential LMBs.

An ion conducting ZIF-8 coating protected PEO based polymer electrolyte for high voltage lithium metal batteries

Solid polymer electrolyte with broad electrochemical stability window is regarded as the most promising candidate for high-voltage lithium metal batteries enabling high specific energy density. However, solid polymer electrolyte without particular protection is not facile to realize stable cycle of LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode at high voltage because of the strong oxidizing property from the direct contact between cathode and electrolyte. Herein, an ion conducting asymmetric poly(ethylene oxide) (PEO) based electrolyte composed of zeolitic imidazolate framework (ZIF-8)@ionic liquid protective coating on NCM811 cathode surface and PEO-based electrolyte with ZIF-8 nanofillers on lithium metal anode is prepared in order to construct high-performance solid-state lithium metal batteries. The as-prepared asymmetric composite electrolyte exhibits a high ionic conductivity of 9.02 × 10-4 S/cm at 60 °C and broad electrochemical stability window of above 4.9 V. Notably, the as-prepared cells exhibit the highest discharge capacity of 150 mAh/g at 0.2C under 60 °C. It is found that the ZIF-8@ionic liquid protective coating effectively prevents the oxidative decomposition of PEO based electrolyte at high voltage and the transition metal dissolution from the cathode. Meanwhile, the growth and penetration of lithium dendrites are also restrained, which shows significant potential for boosting the commercialization of high-voltage lithium metal batteries.

Towards high-performance lithium metal batteries: sol electrolyte generated with mesoporous silica

High-energy lithium metal batteries are considered as a promising alternative for next-generation energy storage systems. However, the uncontrolled lithium-dendrite growth due to the inhomogeneous lithium electrochemical deposition prevents lithium batteries from commercial application. Herein, a sol electrolyte was prepared by the addition of mesoporous silica, SBA-15 to the liquid ester-based LiPF6 electrolyte to induce the formation of a dense protective layer on the lithium metal surface and inhibit the uncontrolled growth of lithium dendrites and the electrolyte consumption. Mesoporous silica with ordered hexagonal nanochannels and abundant surface silicon hydroxyl groups not only facilitates the formation of the sol electrolyte, but also adsorbs the electrolyte, leading to homogeneous lithium ion distribution. The sol electrolytes would generate a dense protective layer on the lithium metal and a robust CEI film on the surface of the cathode materials through an in situ gelation process, suppressing the uncontrolled lithium dendrite growth and improving the stability of the electrolyte. Consequently, high electrochemical performance was demonstrated with the Li||LiNi0.5Co0.2Mn0.3O2 (NCM523) full cells with the sol electrolyte. This work provides a new strategy for improving the performance of lithium metal batteries through the formation of sol electrolytes.

Mechanically robust epoxy resin-based gel polymer electrolyte stabilizing ion deposition for high-performance lithium metal batteries

Lithium metal batteries (LMBs) with extremely excellent energy density exhibit highly potential for future power applications. However, due to the dendrite growth caused by the strong activity of lithium metal, severe safety concerns and low life range are still great challenges for LMBs. Herein, a porous epoxy resin-based gel polymer electrolyte (PEE) with a special structure of the skeletal network fully filled with epoxy resin globules is developed. The PEE membranes with abundant communicating pores channels and rich polar groups (–OH, C–O–C) show high lithium ion conductivity and robust mechanical performance (the Young's modulus of 312 MPa after activation by liquid electrolyte) as well as superior thermal stability (no dimensional change at 250 °C). Furthermore, the typical PEE-2.75 membrane can restrain lithium dendrites growth effectively and stabilize lithium ion deposition (over 1000 h of stable operation at 2 mA cm−2). Therefore, the full cell Li//PEE-2.75//LiFePO4 shows a significant rate capacity of 92.8 mA h g−1 at 5 C and stable cycle performance (capacity maintained at over 82.33% after 195 cycles at 1 C). This work presents a simple and effective way for the application of epoxy resin in high-performance LMB.

Redox-Active Covalent Organic Frameworks with Nickel-Bis(dithiolene) Units as Guiding Layers for High-Performance Lithium Metal Batteries.

Combining the chemistry of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) can bring new opportunities for the design of advanced materials with enhanced tunability and functionality. Herein, we constructed two COFs based on Ni-bis(dithiolene) units and imine bonds, representing a bridge between traditional MOFs and COFs. The Ni-bis(dithiolene)tetrabenzaldehyde as the 4-connected linker was initially synthesized, which was further linked by 4-connected tetra(aminophenyl)pyrene (TAP) or 3-connected tris(aminophenyl)amine (TAA) linkers into two COFs, namely, Ni-TAP and Ni-TAA. Ni-TAP shows a two-dimensional sql network, while TAA is a twofold interpenetrated framework with an ffc topology. They both exhibit a high Brunauer-Emmett-Teller surface area (324 and 689 m2 g-1 for Ni-TAP and Ni-TAA, respectively), a fairly good conductivity (1.57 × 10-6 and 9.75 × 10-5 S m-1 for Ni-TAP and Ni-TAA, respectively), and high chemical stability (a stable pH window of 1-14 for Ni-TAA). When applied in lithium metal batteries as an intermediate layer for guiding the uniform Li electrodeposition, Ni-TAP and Ni-TAA displayed impressive lithiophilicity and high Li-ion conductivity, enabling the achievement of smooth and dense Li deposition with a clear columnar morphology and stable Li plating/stripping behaviors with high Li utilization, which is anticipated to pave the way to upgrade Li metal anodes for application in high-energy-density battery systems.

Role of Mixed Inorganic Additives in Controlling the Dendrite Growth in Lithium Metal Anodes

Here we demonstrate to suppress the dendrite growth and stabilize the LMA using Lithium difluoro(oxalato)borate (LiDFOB) and tetraethyl orthosilicate (TEOS) as primary and secondary additives in commercial LiPF6 salt electrolyte. While the incorporation of LiDFOB additive potentially reduced the overpotential values, thereby improving the cycling stability in comparison to commercial electrolyte in Li/Li symmetric cell, the performance characteristics dramatically enhanced on using TEOS as the secondary electrolyte additive. In addition, rate capabilities of the NMC/Li full cells are apparently higher on using the additives in the electrolyte system. The profound effect is attributed to the formation of film layer on the lithium surface, which eventually regulates the lithium deposition during the electrochemical cycling. Thus, incorporation of multiple inorganic additives in the commercial electrolyte system paves a way in making high performance lithium-metal batteries.

Two-dimensional nanofluidic suppressing anion mobility toward dendrite-free lithium metal anode

Modification of separator with lithium-ion redistributor has been considered to be an effective strategy to evade lithium dendrite by evening lithium-ion concentration on electrode surface. According to the Sand equation, the mobility of anion is also critical to realizing smooth lithium deposition. Herein, a fast cation conductor layer was constructed by assembling exfoliated vermiculite sheets on commercial separator to form vermiculite composite separator (VCS). The negative surface charged 2D nanofluidic channels in VCS repel anions, blocking the shuttle of anions between electrodes. Nevertheless, lithium ions are attracted, and mobility is dramatically enhanced, which increases the lithium-ion transference numbers (tLi+) and intrinsically improves the electrochemical performance. Resultantly, the Coulombic efficiency of Cu//Li battery with VCS is more than 96%, and the voltage polarization of symmetric battery is only a quarter of the commercial separator even at a high current density of 5 mA/cm2. Furthermore, the inorganic nature of the vermiculite sheet endows the VCS with excellent thermal stability. The superior electrochemical performance of VCS highlights the importance of constructing 2D nanofluidic channels and provides new avenues for the development of high-performance and long-lifespan lithium metal batteries.

New insights into designation of single-ion conducting gel polymer electrolyte for high-performance lithium metal batteries

Single-ion conducting polymer electrolytes (SIPEs) are promising separator/electrolyte materials in lithium metal batteries (LMBs) owing to their high lithium-ion transference numbers. However, the low ion conductivity and poor interfacial compatibility limit their practical application. The effective structural design and the highly porous membrane preparation are of significance for surmounting above issues. Here, a high-performance fire-resistant phosphine based SIPE with semi-interpenetrating polymer network is designed and its highly porous electrospun nanofiber membrane ( nf -sIPN-PECB) is subsequently prepared. After interpenetrated by 1 M LiPF 6 in EC/PC electrolyte, the nf -sIPN-PECB/1M LiPF 6 in EC/DMC electrolyte delivers ultrahigh ion conductivity of 2.5 mS cm −1 and excellent interfacial compatibility for achieving LiFePO 4 cathode LMB with a high discharge capacity of 166 mA h g −1 at 0.1C and 110 mA h g −1 at 6.0C. Moreover, the nf -sIPN-PECB/1M LiPF 6 in EC/DMC electrolyte demonstrates a high lithium-ion transference number of 0.64, endowing LMBs with excellent inhabitation of lithium dendrite growth. Therefore, ultra-long lifespan of 1000 cycles for the LMBs with ignorable capacity decay was successfully achieved. Furthermore, the good fire-retardant, high thermal dimensional stability and excellent flexibility drag LMBs out of severe safety hazards. A high-performance fire-resistant phosphine based SIPE (Li-PECB) with semi-interpenetrating polymer network is well-designed for simultaneously achieving the excellent fire-retardancy, good mechanical strength and enhanced ionic conductivity of the highly porous electrospun nanofiber membrane ( nf -sIPN-PECB). The molecular-scale mixture between PVDF-HFP binder and Li-PECB is successfully approached during in-situ polymerization process. • 3D IPNs of highly porous electrospun nanofiber membrane was prepared. • The porous electrospun nanofiber membrane displays enhanced mechanical strength due to 3D IPNs. • The nf -sIPN-PECB display uniform morphology and molecular level dispersion of components. • The enhanced lithium ion transference number was obtained for suppress lithium dendrite growth. • The promising elevated temperature cell performance with high coulombic efficiency was successfully obtained.

High-performance lithium metal battery realized by regulating Li+ flux distribution on artificial-solid-electrolyte-interphase functionalized 3D carbon framework-Li anode

Lithium dendrite issue is the key problem that hampers the practical applications of lithium metal batteries. Regulating Li+ flux distribution on Li anode can effectively tune the Li dendrite growth. Here, we report a novel Li anode composited with artificial-solid electrolyte interphase (A-SEI) functionalized 3D carbon framework seamless bonding Li foil (A-3DCF@Li) that can tune Li+ flux distribution. The synergetic effect among 3D structure, A-SEI, and LiCx in A-3DCF@Li can regulate Li+ flux on Li surface, suppressing Li dendrite growth and boosting the electrochemical performance of lithium metal battery using LiNi0·83Co0.11Mn0.06O2 as cathode materials. The experimental results and theoretical calculation prove the above statement. The work developed here shed light on the development of high-performance lithium metal anode.

Achieve Stable Lithium Metal Anode by Sulfurized-Polyacrylonitrile Modified Separator for High-Performance Lithium Batteries.

To develop a high-energy-density lithium battery, there still are several severe challenges for Li metal anode: low Coulombic efficiency caused by its high chemical reactivity, Li dendrite formation, and "dead" Li accumulation during repeated plating/stripping processes. Especially, lithium dendrite growth imposes inferior cycling stability and serious safety issues. Herein, we propose a facile but effective strategy to suppress lithium dendrite growth through an artificial inorganic-polymer protective layer derived from sulfurized polyacrylonitrile on a polyethylene separator. Benefiting from the lithiated sulfurized polyacrylonitrile and poly(acrylic acid), the flexible and ion-conductive protective layer could regulate Li+ flux and facilitate dendrite-free lithium deposition. Consequently, lithium metal with the meritorious protective layer can achieve a long-term cycling with negligible overpotential rise in Li-Li symmetric cells, even at a high areal capacity of 5 mAh cm-2. Remarkably, such a protective layer enables stable cycling performance of Li-S cell with a high areal capacity (∼9 mAh cm-2). This work provides a valuable exploration strategy for potential industrial applications of high-performance lithium metal batteries.