Carbonization Of Metal-organic Framework Research Articles

Superior supercapacitor performance with tuneable 2D/3D morphological microporous carbons of zeolitic imidazolate frameworks synthesized by recycling mother liquors

Carbonized metal–organic frameworks (MOFs)-based nanoporous carbon materials (NPCs) offer attractive activities in electrochemical energy conversion and storage (EECS) applications; however, there is the need for scalable MOFs production under reduced energy/environmental impact. This study reports a green synthesis route for model zeolitic imidazolate framework (ZIF-8) materials via recycling methanol-based mother liquors (ZIF-RMLx) under room temperature stirring and their carbonized materials (CZC-RMLx) for high-performance supercapacitors. Series of ZIF-RMLx samples produced in four recycles offer rod-/sheet-/polyhedral-like 2D/3D microstructures with tuneable internal and external framework and morphological features. Accordingly, CZC-RMLx, obtained by direct pyrolysis, with high microporosity and surface area of 1500 m2 g−1 deliver excellent capacitance values of 200–340 F g−1, compared to typical MOFs-derived or chemically activated/templated NPCs, produced via extended chemical processing. Structure-relevant and comparative performance analysis reveal insights for improved charge storage and carbonization-dependent graphitization, nitrogen-doping and microporosity-controlled capacitance characteristics in the CZC-RMLx over typical NPCs in literature. The device-level performance with a long-term durability over 21,000 cycles is demonstrated. The practical potential of CZC-RMLx is further evaluated by fabricating solid-state cells and their parallel and series circuit combinations result in overall capacitance and voltage boost to 450 F g−1 and 2.4 V, respectively.

Metal-organic framework-derived LaFeO3@C: An adsorbent for removing organic dyes from water

Metal-Organic Frameworks (MOFs) and MOF-derived materials are emerging as a potential candidate in the field of adsorption owing to their vital properties of high surface area, tunable porosity and diverse functionalities. However, the instability of MOFs in harsh environmental conditions prompted to produce more stable forms of MOF-derived materials for adsorption applications. Carbonization of MOFs is becoming an efficient method to prepare stable metal oxide-carbon hybrids as adsorbents for pollutant removal. This study presents the first-time report on utilizing MIL-100(Fe)-derived mesoporous LaFeO3@C nanocomposites for the effective adsorption removal of methyl orange (MO) and sulforhodamine B (SRB). The nanocomposites having different surface chemistry and textural properties are formed from MOF-gel precursor by varying the calcination temperature in the argon atmosphere. The LaFeO3 nanoparticles in the nanocomposites crystallized into the orthorhombic structure, which is confirmed from the XRD, Micro-Raman and FTIR analysis. The material obtained at 700 °C (LFO@C-700) exhibited higher removal efficiency of 99% and 97.1% towards SRB and MO, respectively. The chemisorption is identified as the main rate-limiting step in adsorption and the isotherm follows the Langmuir model suggesting the monolayer coverage of the adsorbates. The successful elimination of dye contaminants from real water samples and industrial effluents by LFO@C-700 indicates the practical utility of this adsorbent material. Several key chemical interactions, including H-bonding, electrostatic interactions, π-π and cation-π interactions promote the adsorption process. Moreover, the LFO@C-700 nanocomposite shows reusability with sustainable adsorption for repeated experiment cycles, suggesting this adsorbent's cost-effective use in practical applications.

High sensitivity and wide range flexible piezoresistive sensor based on petal-shaped MOF-derived NiCo-NPC

Due to the advantages of high porosity, excellent conductivity, and tunable morphology, carbonized metal-organic framework (C-MOF) is expected to become an ideal material for constructing high-performance flexible pressure sensor. Herein, to achieving the suitable morphology of C-MOF for piezoresistive sensors, a rapid thermal process (RTP) was used for carbonization of NiCo-MOF, and the petal-shaped NiCo alloy nanoparticles/nanoporous carbon composites (NiCo-NPCs) were obtained. Compared with NiCo-NPCs carbonized by common thermal process (CTP), NiCo-NPCs carbonized by RTP exhibit a modified morphology with smaller particle size and larger most frequent pore diameter. Due to the modified morphology, the piezoresistive sensor with RTP-carbonized NiCo-NPCs has a high sensitivity of 62.13 kPa–1 at 0–3 kPa, which is 3.46 times higher than that of the sensor with CTP-carbonized NiCo-NPCs. Meanwhile, the sensor shows an ultra-wide range of 1000 kPa, excellent cycle stability (>4000 cycles), and fast response/recovery time of 25/44 ms. Furthermore, the application of the sensor in dynamic loading test, airflow monitoring, voice recognition, and gesture detection demonstrates its great application prospects. In short, this work investigates the application of carbonized NiCo-MOFs in flexible pressure sensors, and provides a new strategy to improve the performance of piezoresistive sensors with porous carbon derived from MOFs.

Highly tough and conductive hydrogel based on defect-patched reduction graphene oxide for high-performance self-powered flexible sensing micro-system

Tough and conductive reduction graphene oxide (rGO)-based hydrogels have broad application prospects in various flexible wearable electronics. However, an often ignored phenomenon was that numerous defective regions were inevitably formed within the basal plane of rGO during synthesis process, deteriorating the physical characteristics as well as overall performances of wearable devices. Herein, a facile and effective defect patching engineering was proposed to heal rGO by carbonized metal–organic frameworks (CMOF). The fixed CMOF at defect regions acted as a bridge to allow electrons to pass quickly and enhance tolerance of rGO to loaded mechanical energy. The resultant optimized hydrogel containing defect-patched rGO flakes not only possesses satisfied mechanical properties (e.g., tensile strength of 195 kPa) and high electrical conductivity (2.42 S/m), but also exhibits reinforced electric output performances when assembled into triboelectric nanogenerator, supercapacitors and sensor devices. More importantly, the sensor with high sensitivity (gauge factor (GF) of 14.68, short response time of 40 ms) was capable of effective distinguishing complex human activities and accurate detecting the temperature fluctuation of skin within narrow range. As proof-of-concept, the as-synthesized all-in-one flexible intelligent micro-system, composed of power supply, energy storage and sensing units, had proved the great compatibility and feasibility of wearable electronics in detecting and recognizing human expressions, motion and physiological signals. Our findings proposed a reliable defect patching strategy for large-scale production of defect-free 2D carbonaceous materials, boosting the development of high-performance self-powered sensing micro-system in wearable devices.

Development of a novel sensor based on Bi2O3 and carbonized UIO-66-NH2 nanocomposite for efficient detection of Pb(Ⅱ) ion in water environment

Development of an efficient monitoring technology for rapid detection of toxic Pb(Ⅱ) ion in water environments is extremely important. Here, a novel and highly sensitive sensor was prepared using one-step calcination technique, based on Bi2O3 nanoparticles and carbonized metal–organic framework (MOF) nanocomposite. Scanning electron microscopy, transmission electron microscopy, contact angle and X-ray photoelectron spectroscopy characterization methods were used to analyze the morphology and structure of the prepared materials. Based on the electrical double-layer capacitance theory and Raman spectroscopy, changes to the active sites of different modified materials were investigated. Besides, differential charge densities and adsorption energies of the different modified materials in Zr-O clusters were calculated using density functional theory (DFT). A Bi2O3 and carbonized UIO-66-NH2 (Bi2O3/C-UIO-66-NH2) -modified glassy carbon electrode was used to detect Pb(Ⅱ) by differential pulse anodic stripping voltammetry. Under optimal experimental parameters, the developed electrochemical sensor has a wide linear range (2–130 μg/L) and a low detection limit (0.05 μg/L). Meanwhile, the sensor has excellent stability, repeatability, and anti-interference properties and has been successfully applied to detect Pb(Ⅱ) in actual water samples. The results of this paper show that our developed sensor an efficient and rapid sensor technology for monitoring lead in water environment.

Structured nano materials derived from MOF

At the present time, zeolitic imidazolate framework-8 is used in multiple areas from wastewater treatment, membranes, drug delivery and catalysis to photo electronics owing to their inherent exclusive pore structure and high specific surface area as well as their advanced thermal and chemical stability. The molecular differentiation qualities of the product that is ZIF-8 will affect by porosity and pore size distribution and this affects the membrane performance in terms of permeability. Systematic porous materials are broadly achieved by classical hard and soft templating techniques leading to diverse pore size distributions and morphologies. In recent years, ZIF-8 derived from Metal-organic frameworks (MOFs) which is a subclass of Metal-organic frameworks (MOFs) and these MOFs are growing as a novel category of nanoporous materials with large surface areas and small pore size distributions. In the present work, we have synthesized and characterized carbonized metal–organic framework, in the case of ZIF-8 for wastewater treatment processes. Nano ZIF-8 is prepared via a single step room temperature crystallizationwith 2-MIM and zinc nitrate hexahydrate as precursor materials. Prepared ZIF-8 materials were characterized by DLS, XRD, and SEM analysis for identifying morphological and compositional changes. Carbonized ZIF-8 (CZIF-8) is produced via the single-step carbonization technique by decomposing ZIF-8 in an inert atmosphere at 1000 °C. Parent material is compared with the carbonized material for morphological and elemental composition changes. ZIF-8 and CZIF-8 were utilized as an additive in the fabrication of a mixed matrix membrane to modified polysulfone membrane for wastewater treatment. As a result, compared with plain polysulfone membrane has a pure water flux of 50.5L/m2h and ZIF-8/PSF Mixed Matrix Membrane has a pure water flux is 456.09 L/m2h, but CZIF-8/PSF MMM is 521.12 L /m2 h, which is much greater than that of pure PSF and 4 wt% ZIF-8/PSF membranes. as shown in Fig 0.7.

An emerging machine learning strategy for electrochemical sensor and supercapacitor using carbonized metal–organic framework

• A machine learning strategy was applied for electrochemical sensor and supercapacitor. • The carbonized metal–organic framework showed excellent electrochemical response for niclosamide (NA) and good capacitance. • Both adsorption and binding energy were theoretically calculated and the structure of prepared material was optimized. Machine learning (ML) plays an important role in the electrochemical application of electrode materials. In this work, an emerging machine learning strategy for both electrochemical sensor and supercapacitor using carbonized metal–organic framework (C-ZIF-67) is proposed. The morphology and element analysis of C-ZIF-67 are characterized and further demonstrate the presence of C, N, O, Co elements. The ML model based on artificial neural network (ANN) algorithm as a powerful tool to realize intelligent analysis of niclosamide (NA), the derivative technique as an auxiliary means of voltammogram treatment to reduce personal error from data-reading and improve the sensitivity of electrochemical responses at very low concentrations, and the theoretical calculation is employed for both adsorption and binding energy, optimized structure of the prepared sensing material. The developed sensor displays excellent electrochemical response about 196.6-fold improvement compared with the bare GCE for NA, wider linear ranges of intelligent analysis from 1 nM to 9 μM with low limit of detection of 0.3 nM, and satisfactory practicability. ML model with ANN algorithm is also employed for predicting the performance of supercapacitor. The supercapacitor shows good performance with capacitance of 336.67 F/g at the current density of 2 A/g and excellent prediction with acceptable errors. This work will provide a new strategy for the development and electrochemical application of bifunctional electrode materials using the ML technique combined with theoretical calculation.

Design of M-N-C Catalyst By Spray Pyrolysis and Pseudomorphic Transformation As Efficient Electrocatalysts for Oxygen Reduction Reaction

Transition metal catalysts with Metal-N-C (M-N-C) sites has been investigated as an alternative of the noble metal catalyst for the oxygen reduction reaction (ORR), which occurs on a cathode of fuel cell. Among the methods of preparing various M-N-C catalysts, carbonized metal organic frameworks (MOF) are the one of the simple ways to synthesize nitrogen-doped carbon. MOF are known highly porous crystalline solids constructed from metal ions or clusters covalently linked by organic ligands. The tunability of their composition, architecture, and properties has has led to advances in drug delivery, catalysis, sensors, optoelectronics, electrochemistry, gas separation and gas adsorption. Although many studies have been reported that M-N-C catalysts have better performance than Pt catalysts, but most have been reported in alkaline media, and Fe-N-C catalysts have been mainly studied in acidic media. Fe-N-C catalysts have excellent performance; the new M-N-C catalyst should be replaced as it is less stable due to the fenton reaction. In this study, we report the synthesis of a melamine-encapsulated Co-ZnO-C composite as a precursor and template for zeolite-imidazole-frameworks (ZIF-8). This approach allows formation of Co-N-C for constructing unique structures at meso- and macropore scales, while maintaining microporosity. Density functional theory analysis confirms the superior stability of the Co-N-C catalyst over other M-N-C catalysts (M = Fe, Ni, Cr, and Mn). The Co-NC catalyst with a developed pore structure shows remarkable durability (6.7 % performance degradation for 100 h) and full cell performance in H2/O2 under 1 bar of backpressure (723 mW/cm2 of maximum power density).

Ultrahigh Sensitive Flexible Piezoresistive Sensor with Carbonized Metal–Organic Framework Fe3O4@MIL-100(Fe)

The piezoresistive sensor is an important device for sensing pressure and strain in flexible electronics. The application of composite conductive nanomaterials is helpful to obtain high-performance and multifunctional flexible piezoresistive sensors. Herein, using carbonized Fe3O4@MIL-100(Fe) as a composite conductive nanomaterial, an ultrahigh-sensitivity flexible piezoresistive sensor was achieved by a laser-processed template. Due to the porous Fe3O4@MIL-100(Fe) conductive nanomaterials and microridges on the styrene–isoprene–styrene substrate, the sensitivity of the sensor reaches 1727.46 kPa–1 in the pressure range of 0–50 Pa, which has a significant advantage over the reported sensors. Meanwhile, the sensor exhibits good cycling stability (>1500 cycles), a fast response of 24 ms, an instant recovery of 15 ms, excellent reversibility, and an antielectromagnetic interference capability. For practical applications, the sensor was applied for monitoring body physiological signals such as speech and artery pulses, indicating that the sensor is suitable for health monitoring. Moreover, using carbonized metal–organic frameworks with functional nanoparticles as conductive nanomaterials in the sensing unit provides a feasible way to develop multifunctional flexible piezoresistive sensors.

Effect of carbonization temperature on electrochemical properties of ZnO@C anode materials

• Synthesis of ZnO@C Composites by Carbonization of Metal Organic Frameworks at Different Carbonization Temperatures. • Polygonal ZnO@C composites were synthesized only at 650 °C. • Materials synthesized at 650 °C have best electrochemical properties as anode materials. A novel ZIF-8-derived nano ZnO@C composite used as anode materials for lithium-ion batteries was successfully synthesized by facile high temperature carbonization. The influence of carbonization temperature on the composition and morphology of the synthesized samples was researched. The results indicated that the sample at carbonization temperature 650 °C was the well-crystallized hexagonal structure and optimized particle size. Meanwhile, the reversible capacity of the ZIF-8-derived nano ZnO@C composite at 650 °C retained 427.6 mAh g −1 after 50 cycles. Moreover, the sample exhibited an excellent initial discharge capacity with 1948.6 mAh g −1 . The hexagonal structure in the ZIF-8-derived nano ZnO@C is not only very stable, but the volume expansion in the process of electrochemical reaction can be effectively inhibited, which makes it demonstrate stable long cycle performance and excellent rate performance.

Nano-Porous Composites of Activated Carbon–Metal Organic Frameworks (Fe-BDC@AC) for Rapid Removal of Cr (VI): Synthesis, Adsorption, Mechanism, and Kinetics Studies

Metal–organic frameworks (MOFs) are a group of porous materials that display potential in the elimination of toxic industrial compounds (TICs) from polluted water streams. However, their applications have so far been held up by issues due to their physical nature and cost. In this study, activated carbon (AC) is modified with an Fe-based MOF, iron terephthalate (Fe-BDC). A facile and cost-effective impregnation method is used for enhanced removal from aqueous solutions. The new adsorbent is characterized by SEM, FTIR, PXRD, and BET. The composite displays excellent uptake of Cr (VI) when compared to un-impregnated AC with a maximum monolayer adsorption capacity of 100 mg·g−1. The experimental data shows a high correlation to the Langmuir adsorption model. The adsorption kinetic study reveals that the adsorption of Cr (VI) to Fe-BDC@AC obeys the pseudo-first-order equation. The composite shows high reusability after five cycles and high adsorption rates reaching equilibrium in just 50 min. Such properties make the nanocomposite promising for water decontamination on larger scales compared to powder-based alternatives, such as individual MOF crystals.

Theoretical and Experimental Investigation of Bifunctional Oxygen Electrocatalysts from Carbonized MOFs

Multifunctional electrocatalysts are the key to sustainable energetics. An efficient bifunctional catalyst material that can catalyze both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is required for rechargeable metal-air batteries. Although recent research has shown materials that can compete with the standard expensive noble metal catalysts (Pt and RuO2), further advances are needed. Most notable class of new catalysts includes carbonized metal-organic frameworks (MOFs), which leads to active single site catalysts. Furthermore, computational chemistry-based methods are essential to explain the observed activity and provide further guidelines to the synthesis of better performing materials. Here we give an overview of recent advances in computationally guided electrocatalyst evaluation. We highlight the limitations observed by thermodynamics-based modelling and discuss proposed solutions for improved catalytic materials.

Encapsulation of selenium in MOF-derived N,O-codoped porous flower-like carbon host for Na-Se batteries

Na-Se batteries have their drawbacks such as large volumetric expansion and shuttle effect related to generation of soluble sodium polyselenides. To address these issues, a nitrogen and oxygen codoped flower-like porous carbon host is derived from a Ni-based metal–organic framework (MOF) for Se storage. The use of 4,4′-oxybisbenzoic acid and 4,4′-dimethyl-2,2′-bipyridyl ligands ensure the in-situ doping of the carbon host with oxygen and nitrogen upon carbonization of MOF, which increases its polarity and restricts the diffusion of selenium. Highly porous microflower-like carbon morphology provides sufficient space for Se storage. To avoid undesirable aggregation of Se particles which happens when using conventional melt-diffusion method, we employed a vapor-infiltration method for Se loading, which ensures the homogeneous dispersion of selenium and high utilization of pores in the carbon host. Density functional theory calculations confirmed that the increased polarity of the carbon host due to N,O codoping promotes the adsorption of polyselenides. When tested as a cathode for sodium-selenium battery, the optimized carbon/selenium composite shows an excellent electrochemical performance.

Impact of hydrofluoric acid treatment on the composition, electrical conductivity, and structure of carbonized metal–organic frameworks

AbstractMetal–organic frameworks (MOFs) containing V, Cr, Mn, Fe, Co, Ni, Cu, and Zr were pyrolyzed under nitrogen flow. The products of carbonized MOFs (CMOFs) contain metal oxides and carbonaceous residues, which were characterized by powder X‐ray diffraction (PXRD), electrical conductivity (EC), and Raman spectroscopy. To remove the metallic components in CMOFs, hydrofluoric acid (HF) treatment was performed. PXRD analysis showed that only Mn, Co, Ni, and Zr, but not V, Cr, Fe, and Cu, could be completely removed from CMOFs after HF treatment. In fact, PXRD analysis also revealed that during the formation of CMOFs, not only metal oxides, but also metal carbides were formed. The change of the EC of CMOFs after HF treatment was found to be mainly contributed from the metal components, whereas the carbon (graphitic) components played minor roles. The effect of HF treatment on the structure of CMOF was not significant as verified by the Raman analysis of the intensity ratio between D band and G band.

Research progress on nanoporous carbons produced by the carbonization of metal organic frameworks

Research progress on nanoporous carbons produced by the carbonization of metal organic frameworks

Research progress on nanoporous carbons produced by the carbonization of metal organic frameworks

Nanoporous carbons (NPCs) are widely used in gas adsorption, catalysis and electrochemistry because of their high specific surface area, good thermal and chemical stability, etc. Although a lot of work has been done, there are still great challenges in the fabrication of NPCs. Metal organic frameworks (MOFs) with tailorable structures have the advantages of a regular and adjustable pore size, high porosity and high specific surface area, and have proved to be ideal precursors for the preparation of NPCs. To better grasp the state of the art in the preparation of NPCs, we review recent research progress on the fabrication of NPCs by the carbonization of MOFs, with a focus on the carbonization of different combinations of MOFs and guest precursors, both to tune the resulting pore sizes/textures and surface chemical structures/species and to improve the electrical conductivity and structural stability of the product in different applications.

A systematic correlation between morphology of porous carbon cathode and electrolyte in lithium-sulfur battery

Porous carbon has been applied for lithium-sulfur battery cathodes, and carbonized metal–organic framework (MOF) is advantageous in tuning the morphology. Herein, we have systematically synthesized water-distorted MOF (WDM) derived porous carbon via controlling the proportion of both water in a mixed solvent (dimethylformamide and water) and ligand in MOF-5 precursors (metal and ligand), which is categorized by its morphology (i.e. Cracked stone (closed), Tassel (open) and Intermediate (semi-open)). For example, decrease in water and increase in ligand content induce Cracked stone WDMs which showed the highest specific surface area (2742–2990 m2/g) and pore volume (2.81–3.28 cm3/g) after carbonization. Morphological effect of carbonized WDMs (CWDMs) on battery performance was examined by introducing electrolytes with different sulfur reduction mechanisms (i.e. DOL/DME and ACN2LiTFSI-TTE): Closed framework effectively confines polysulfide, whereas open framework enhances electrolyte accessibility. The initial capacities of the batteries were in the following order: Cracked stone > Intermediate > Tassel for DOL/DME and Intermediate > Tassel > Cracked stone for ACN2LiTFSI-TTE. To note, Intermediate CWDM exhibited the highest initial capacity and retained capacity after 100 cycles (1398 and 747 mAh/g) in ACN2LiTFSI-TTE electrolyte having advantages from both open and closed frameworks. In sum, we could correlate cathode morphology (openness and pore structure) and electrolyte type (i.e. polysulfide solubility) with lithium-sulfur battery performance.

Three-phase composites of NiFe2O4/Ni@C nanoparticles derived from metal-organic frameworks as electrocatalysts for the oxygen evolution reaction

Composite electrocatalysts of carbon and metals or metal compounds with homogeneous active sites can be obtained through the carbonization of metal organic framework (MOF) materials under inert atmosphere. In this work, a three-phase composite electrocatalysts NiFe2O4/Ni@C were prepared via pyrolysis from self-assembled MOF nanosheets aggregates. The excellent electrocatalytic activity of the obtained electrocatalysts with various Ni:Fe ratios is demonstrated. Especially, the NiFe2O4/Ni@C sample with the mole ratio of Ni:Fe = 1:1 can use the overpotential (η) of 330 and 423 mV to drive 10 and 50 mA cm−2 respectively. After 80 000 s/22 h, the current density could retained 90% of the initial current density. The excellent activity and stability of the electrocatalysts are attributed to nickel and iron ions with uniform dispersion at atomic level in the NiFe2O4 phase and the synergistic effect of nickel and NiFe2O4 nanoparticles with amorphous carbon atoms or nanoparticles around.

Carbon Cloth: High Areal Capacity Dendrite‐Free Li Anode Enabled by Metal–Organic Framework‐Derived Nanorod Array Modified Carbon Cloth for Solid State Li Metal Batteries (Adv. Funct. Mater. 2/2021)

In article number 2001973, Li-Zhen Fan and co-workers report a carbonized metal–organic framework nanorod modified carbon cloth for stable lithium metal anodes. Benefiting from the advantages of an interconnected carbon-based skeleton and lithiophilic nanostructured layer, the NRA-CC electrode provides significant improvements in electrochemical performance and safety, which provides fresh insight into the design principles of a dendrite-free Li metal anode.

High Areal Capacity Dendrite‐Free Li Anode Enabled by Metal–Organic Framework‐Derived Nanorod Array Modified Carbon Cloth for Solid State Li Metal Batteries

AbstractLi metal is one of the most promising anode materials for high energy density batteries. However, uncontrollable Li dendrite growth and infinite volume change during the charge/discharge process lead to safety issues and capacity decay. Herein, a carbonized metal–organic framework (MOF) nanorod arrays modified carbon cloth (NRA‐CC) is developed for uniform Li plating/stripping. The carbonized MOF NRAs effectively convert the CC from lithiophobic to lithiophilic, decreasing the polarization and ensuring homogenous Li nucleation. The 3D interconnected hierarchal CC provides adequate Li nucleation sites for reducing the local current density to avoid Li dendrite growth, and broadens internal space for buffering the volume change during Li plating/stripping. These characteristics afford a stable cycling of the NRA‐CC electrode with ultrahigh Coulombic efficiencies of 96.7% after 1000 h cycling at 2 mA cm−2 and a prolonged lifespan of 200 h in the symmetrical cell under ultrahigh areal capacity (12 mAh cm−2) and current (12 mA cm−2). The solid‐state batteries assembled with the composite Li anode, high‐voltage cathode (LiNi0.5Co0.2Mn0.3O2), and composite solid‐state electrolyte also deliver excellent cyclic and rate performance at 25 °C. This work sheds fresh insights on the design principles of a dendrite‐free Li metal anode for safe solid‐state Li metal batteries.