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Carbon material has emerged as a highly promising anode for sodium‐ion batteries (SIBs) due to its abundance of resources, cost‐effectiveness, and high carbon yield. This work elaborately designs the precursor structure for the self‐assembly of melamine‐cyanuric acid on the anthracite surface through hydrogen bonding, and successfully constructs N‐doped carbon with tailored microstructure and expanded interlayer spacing. Serving as anode for SIBs, the optimized sample delivers high specific capacity (371.3 mAh g−1 at 0.05 A g−1), superior rate capability (295.8 mAh g−1 at 10.0 A g−1), and excellent ultra‐long cycling performance (the retention of 91.5% after 3000 cycles at 0.5 A g−1). The systematic investigations reveal the enhancement of sodium‐ion storage in the low‐voltage plateau region involving the interlayer intercalation coupled with nanopores filling. It is discovered that the microporous structure formed by the appropriate graphite sheet angle influences the migration and storage of sodium ions. Density functional theory calculations indicate that the adsorption capacity for sodium ion is enhanced and the migration energy barrier perpendicular to the graphite layer is reduced at the appropriate angle of 8°. This study provides novel insights into the sodium‐ion storage mechanism, offering guidance for the better design of anthracite‐based carbon anode with superior performance. [ABSTRACT FROM AUTHOR]

Maintaining body temperature within safe and comfortable range is crucial; however, thermoregulatory materials face challenges in variable environments and extreme application scenarios. Here, a unique dual air‐gelation strategy is developed to synthesize carbon aerogel nanofiber metafabric for energy‐harvesting thermoregulation. By manipulating polyacrylonitrile/water interaction and charge density of the solution, phase separation and Coulombic repulsion in electrospun jets are promoted, forming curly nanofibers with internal nanopores (size 30–60 nm) that entangle to create nanofibrous dual‐aerogel structure; the carbon aerogel nanofiber metafabric is obtained following pre‐oxidation and optimized graphitization. The resulting metafabric exhibits high elasticity, robust temperature resistance from −196 to 600 °C, exceptional thermal insulation performance, high‐efficiency electrothermal capability (adjustable from 15 to 150 °C), and photothermal property (radiation raised temperature by 22 °C). This work provides rich possibilities to develop advanced carbon nanomaterials for thermal management. [ABSTRACT FROM AUTHOR]

Optimized sodium ion battery (SIB) carbon anodes with high stability supporting high power densities are a much‐needed material class and therefore intensively researched. The optimum graphitization degree to accommodate sodium ions, while providing high conductivity, as well as the influence of particle size distribution or pore sizes on the performance of carbon anodes, is one of the most discussed topics in this field. While a lot of studies have been published discussing these questions, the convoluted nature of these parameters, originating from material synthesis constraints, usually prevents their independent optimization. Based on Mesoporous N‐doped Carbon Nanospheres (MPNC) as model carbon material systems, the graphitization temperaturefor spherical particles with a monomodal particle size distribution (≈280 nm) and a narrow pore size distribution (≈30 nm) is optimized for faradaic sodium ion storage (plateau capacity) and electrodes with a very high power density of 2680 W kg−1 at 1000 mA g−1 and a remarkable capacity retention over 2000 cycles of 86 %, only losing 0.04 % of its specific capacity per cycle, are demonstrated. [ABSTRACT FROM AUTHOR]

Facilitating the transition and new application of fossil energy sources are crucial to attaining carbon neutrality. Conversion of coals into graphitic carbons represents an effective route to achieve their high‐value utilization, while this process always involves corrosive/toxic chemical reagents and time‐intensive heating treatment. Here, this work reports a green, rapid, and efficient flash Joule heating (FJH) technique to produce high‐quality carbons from diverse coals within 1 s. The surface groups, defects, and graphitization degree of the resultant carbon materials are controlled during the instantaneous thermal shock process, and the relationships between the coal structures and the product properties are established. The results suggest that the anthracite with high coalification degree tends to form highly graphitic carbons at a peak temperature of ≈3300 K, presenting higher rate capability (79.1% capacity retention at 30 A g–1) and low relaxation time constant (τ0 = 0.27 s) toward capacitive energy storage. Besides, the flash carbon materials derived from lignite and bituminous coal with low coal rank show better capacitive performance with capacity above 80 F g–1 at 1 A g–1. This study evidences that the FJH technology holds great potential to steer coals into valuable carbon materials. [ABSTRACT FROM AUTHOR]

Potassium‐ion hybrid capacitors (PIHCs) are regarded as one of the promising candidates for large‐scale energy storage technologies. Nevertheless, the lack of suitable anode materials combined with fast ion diffusion kinetics and favorable cycle stability restricts their application. Herein, a catalyst‐confined graphitization strategy is proposed to synthesize low‐cost coal‐based carbon anodes, which have controllable heteroatom co‐doping and rich defect sites, together with local graphitic domains. Density functional theory calculations and kinetic analysis are performed to uncover the coupling effect for heteroatom dual‐doping and defective structures. Importantly, the introduction of graphitic domains ensures good electric conductivity and charge transfer kinetics while preserving rich defects and active sites. The optimized NC‐950 exhibits superior potassium storage capacity, which delivers a high reversible specific capacity (363.3 mAh g−1), impressive rate capability (93.9 mAh g−1 at 2 A g−1), and stable cycling performance. As a practical device application, the PIHCs (NC‐950//AC) are assembled using the NC‐950 anode and commercial activated carbon (AC) cathode, which exhibits the maximum energy density of 97.0 Wh kg−1 and excellent cycling stability (10 000 cycles). Significantly, this work unveils a new pathway to developing low‐cost and fast reaction kinetics carbon anode for advanced electrochemical supercapacitors. [ABSTRACT FROM AUTHOR]

Fine control over the graphitization level of carbonized nanostructures can play a strategic role in tuning the crystallization of supported nanocatalysts, thereby modulating the kinetics of catalysis. However, realizing the synergistic interplay of graphitization‐tunable support and supported catalysts poses a significant challenge. This study proposes a current pulse‐induced ultrafast strategy for developing MOF‐derived graphitic nano‐leaves (GNL) and supported ultrafine ruthenium nanoclusters exhibiting selective crystallization states depending on the tunable graphitization level of GNL. The resulting ultrafine (≈0.7 nm) amorphous‐ruthenium nanoclusters linked with GNL (a‐Ru@GNL500) exhibit state‐of‐the‐art performance in the hydrogen evolution reaction (HER), requiring very low overpotentials of only 23.0 and 285.0 mV to achieve current densities of 10 and 500 mA cm−2, respectively. Furthermore, a‐Ru@GNL500 demonstrates exceptional operational stability for 100 h under high HER currents of 200 and 400 mA cm−2. Density functional theory reveals that the unique electronic structure of a‐Ru and the cooperative effect of cobalt embedded in the graphitic layer lower the occupancy of the antibonding orbital, resulting in an accelerated HER process. Additionally, the unique electronic structure, highly conducting GNL, and efficient bubble release dynamics of super‐aerophobic a‐Ru@GNL500 contribute to reduced overpotentials, particularly at high HER current densities. [ABSTRACT FROM AUTHOR]

At present, most synthetic graphite materials commonly used as anode active ingredients in lithium‐ion cells are produced by graphitization of petroleum cokes. The carbon footprint associated with synthetic graphite production is significant. Thus, bio‐derived and cheap precursors, such as saccharides, would be an attractive alternative for the sustainable production of graphitic carbons. However, they are non‐graphitizing at temperatures as high as 3000 °C, preserving the curved, fullerene‐like structure of graphene layers and microporosity. Consequently, many lithium ions are consumed during the formation of solid electrolyte interphase films and passivated in the nanovoids. Here, a method for the production of pure, crystalline, graphitic materials based on sucrose disposed of microporosity is presented, which also works with a variety of saccharides and other organic precursors of hard carbons—generally considered incapable of such transformation. This process employs catalytic graphitization by Si particles at high temperatures. The electrochemical response of such derived sucrose‐based graphite in Li‐ion half‐cells demonstrated its feasibility to serve as an anode active material for rechargeable Li‐ion batteries. [ABSTRACT FROM AUTHOR]

Nitrogen-containing carbons (NC) are a class of sustainable materials for selective CO2 adsorption. A versatile concept is introduced to fabricate flexible NC-based sensor architectures for room-temperature sensing of CO2 in a one-step laser conversion of primary films cast from abundant precursors. By the unidirectional energy impact in conjunction with depth-dependent attenuation of the laser beam, a layered sensor heterostructure with a porous transducer and active sensor layer is formed. Comprehensive microscopic and spectroscopic cross-sectional analyses confirm the preservation of the high content of imidazolic nitrogen in the sensor. The performance is optimized in terms of material morphology, chemical composition, and surface chemistry to achieve a linear relative resistive response of up to ΔR/R0 = −14.3% (10% of CO2). Thermodynamic analysis yields ΔadsH values of −35.6 and 34.1 kJ·mol−1 for H2O and CO2, respectively. The sensor is operable even in humid environments (e.g., ∆R/R0,RH = 80% = 0.53%) and shows good performance upon strong mechanical deformation.

Given the merits of affordable cost, superior low‐temperature performance, and advanced safe properties, sodium‐ion batteries (SIBs) have exhibited great development potential in large scale energy storage applications. Among various emerging carbonaceous anode materials applied for SIBs, hard carbon (HC) has recently gained significant attention regarding their relatively low cost, wide availability, and optimal overall performance. However, the insufficient initial Coulombic efficiency (ICE) of HC is the main bottlenecks, which is inevitably hindering their further commercial applications. Herein, an in‐depth holistic exposition about the reasons causing the unsatisfied ICE and the recent advances on effective improvement strategies are comprehensively summarized in this review, which have been divided into two aspects including the intrinsic property (degree of graphitization, pore structure, defect, et al.) and the extrinsic factor (electrolyte, electrode materials, et al.). In addition, future prospects and perspectives on HC to enable practical application in SIBs are also briefly outlined. [ABSTRACT FROM AUTHOR]

Recycling the degraded graphite is becoming increasingly important, which can helped conserve natural resources, reduce waste, and provide economic and environmental benefits. However, current regeneration methods usually suffer from the use of harmful chemicals, high energy and time consumption, and poor scalability. Herein, we report a continuously high‐temperature heating (≈2000 K) process to directly and rapidly upcycle degraded graphite containing impurities. A sloped carbon heater is designed to provide the continuous heating source, which enables robust control over the temperature profile, eliminating thermal barrier for heat transfer compared to conventional furnace heating. The upcycling process can be completed within 0.1 s when the degraded graphite rolls down the sloped heater, allowing us to produce the upcycled graphite on a large scale. High‐temperature heating removes impurities and enhances the graphitization degree and (002) interlayer spacing, making the upcycled graphite more suitable for lithium intercalation and deintercalation. The assembled upcycled graphite||Li cell displays a high reversible capacity of ≈320 mAh g−1 at 1 C with a capacity retention of 96% after 500 cycles, comparable to current state‐of‐the‐art recycled graphite. The method is a chemical‐free, rapid, and scalable way to upcycle degraded graphite, and is adaptable to recycle other electrode materials. [ABSTRACT FROM AUTHOR]

Organic redox‐active materials are promising electrode candidates for lithium‐ion batteries by virtue of their designable structure and cost‐effectiveness. However, their poor electrical conductivity and high solubility in organic electrolytes limit the device's performance and practical applications. Herein, the π‐conjugated nitrogen‐containing heteroaromatic molecule hexaazatriphenylene (HATN) is strategically embedded with redox‐active centers in the skeleton of a Cu‐based 2D conductive metal–organic framework (2D c‐MOF) to optimize the lithium (Li) storage performance of organic electrodes, which delivers improved specific capacity (763 mAh g−1 at 300 mA g−1), long‐term cycling stability (≈90% capacity retention after 600 cycles at 300 mA g−1), and excellent rate performance. The correlation of experimental and computational results confirms that this high Li storage performance derives from the maximum number of active sites (CN sites in the HATN unit and CO sites in the CuO4 unit), favorable electrical conductivity, and efficient mass transfer channels. This strategy of integrating multiple redox‐active moieties into the 2D c‐MOF opens up a new avenue for the design of high‐performance electrode materials. [ABSTRACT FROM AUTHOR]

The employment of ultra‐thin lithium metal anode with high loading cathode is the key to realizing high‐energy‐density rechargeable lithium batteries. Ultra‐thin lithium foils are routinely loaded on a copper substrate in batteries, however, the close contact of these two metals causes galvanic corrosion in the presence of electrolyte, which results in irreversible consumption of lithium and decomposition of electrolyte. Herein, a lightweight and highly conductive flexible graphite paper (GP) is applied to replace Cu foil as the current collector for lithium metal anode. It is demonstrated that the application of GP prevents galvanic corrosion and maintains intimate and steady contact between Li foil and GP current collector during cycling, thereby improving the electrochemical performance of the battery. A 1.08 Ah pouch cell assembled with Li@GP anode and LiNi0.8Co0.1Mn0.1O2 cathode exhibits a long lifetime of 240 cycles with a capacity retention of 91.6% under limited Li, high cathode loading and lean electrolyte conditions. [ABSTRACT FROM AUTHOR]

Lithium metal is considered as a promising anode for its high energy density and low redox potential. However, dendrite growth and electrolyte‐lithium reaction lead to poor cycling stability of lithium anodes. Herein, a space‐confined strategy is proposed to realize stable Li metal anode by constructing a nonplanar interface with flexible tent‐like nanocavities. The tent‐like interface is achieved through the self‐assembly of graphene oxide on zinc nanosheets, accompanied by the spontaneous formation of ZnOC bond. Remarkably, the ZnOC bond immobilizes the graphene oxide layer to ensure tent‐like structural integrity, and shows excellent lithophilicity to induce homogeneous lithium deposition within nanocavities. Furthermore, the process of Li plating/stripping is confined inside tent‐like nanocavities to effectively decrease electrolyte content contact with fresh Li, which reduces hazardous electrolyte‐lithium reaction and thus eliminates continuous consumption of Li metal. Consequently, the symmetrical cells with the tent‐like interface deliver excellent long cycling performance over 1600 h at 1 mA cm−2, and full batteries show high‐capacity retention of 94.6% after 3000 cycles at 5 C. This strategy provides a unique flexible tent‐like interface to achieve stable lithium metal anode. [ABSTRACT FROM AUTHOR]

Hard carbons have attracted increased interest as an alternative of graphite for the anodes of potassium‐ion batteries (PIBs). However, the practical applications of hard carbon anodes are hampered by their low capacities, high potential platforms, and large potential hysteresis. Hard carbons coupled with graphitic nanodomains can achieve stable potassium‐ion storage behaviors with low potential platforms and low potential hysteresis. Herein, the crystalline lattice in hard carbon anodes is tuned by incorporating graphene oxide in renewable lignin precursors. The modified hard carbon (i.e., QLGC) anodes show graphitized nanodomains in the carbon matrix with an expanded interlayer spacing (0.42 nm) in the amorphous regions, which results in a stable potassium‐ion (de)intercalation behavior. Thus, the QLGC anodes exhibit a high capacity of 164 mAh g−1 with low potential hysteresis in the low potential platform region. Moreover, the QLGC anode delivered a highly stabilized capacity of 283 mAh g−1 at 50 mA g−1, a high‐rate capability, and stable cycling performance. Furthermore, the charge storage mechanisms of QLGC anode are elucidated by electro‐kinetic analysis and ex/in situ physicochemical characterizations. This study opens a new avenue for designing hard carbon anodes with engineered crystalline lattices toward practical PIBs. [ABSTRACT FROM AUTHOR]

It is commonly accepted that the increased degree of graphitization leads to a higher electrical conductivity of carbon materials. However, more and more evidence reveals that heteroatom doping on carbon host can also improve the conductivity, owing to the dopant atoms contributing to higher charge delocalization and density of donor states near Fermi level. The reality is, such conductivity improvement from doping is often overwhelmed by graphitized carbon. Although heteroatom‐doped carbon is widely used as active materials in the fields of energy storage and electrocatalysis, which still requires extra carbon‐based conductive additives to enhance the overall conductivity. In this stu, it is demonstrated that the electrical conductivity of finely designed nitrogen‐doped carbon is even beyond the commercialized carbon conductors over 3.5 times, endowing such conductive agent‐free electrode material an excellent performance in an all‐solid‐state flexible supercapacitor. The theoretical simulation further demonstrates that N‐doped sp2/sp3 hybrid carbon can migrate the Fermi level to the conduction band, leading to an n‐type conductivity due to the additional electrons caused by the N dopant. [ABSTRACT FROM AUTHOR]

Nitrogen‐containing carbons (NC) are a class of sustainable materials for selective CO2 adsorption. A versatile concept is introduced to fabricate flexible NC‐based sensor architectures for room‐temperature sensing of CO2 in a one‐step laser conversion of primary films cast from abundant precursors. By the unidirectional energy impact in conjunction with depth‐dependent attenuation of the laser beam, a layered sensor heterostructure with a porous transducer and active sensor layer is formed. Comprehensive microscopic and spectroscopic cross‐sectional analyses confirm the preservation of the high content of imidazolic nitrogen in the sensor. The performance is optimized in terms of material morphology, chemical composition, and surface chemistry to achieve a linear relative resistive response of up to ΔR/R0 = −14.3% (10% of CO2). Thermodynamic analysis yields ΔadsH values of −35.6 and 34.1 kJ·mol−1 for H2O and CO2, respectively. The sensor is operable even in humid environments (e.g., ∆R/R0,RH = 80% = 0.53%) and shows good performance upon strong mechanical deformation. [ABSTRACT FROM AUTHOR]

Densely assembled graphene‐based membranes have attracted substantial interest for their widespread applications, such as compact capacitive energy storage, ion/molecular separation, gas barrier films, and flexible electronics. However, the multiscale structure of densely packed graphene membranes remains ambiguously understood. This article combines X‐ray and light scattering techniques as well as dynamic electrosorption analysis to uncover the stacking structure of the densely stacked reduced graphene oxide (rGO) membranes. The membranes are produced by reducing graphene oxide (GO) membranes with hydrazine, during which the colloidal interactions between GO sheets are modulated by the electrolyte solution. In contrast to the common notion that direct reduction of densely assembled GO sheets in parallel tends to result in significant "graphitization", this article unexpectedly discovers that the resultant densely packed rGO membrane can still retain the interconnected network nanochannels and show good capacitive performances. This inspires the development of a hierarchical structural model to describe the densely packed rGO membranes. This article further shows that the nanochannel network can be fine‐tuned at the sub‐nanometer level by tailoring the salt concentration and the reduction temperature to render exceptional volumetric capacitance and good rate performance for rGO membranes even with increased packing density. [ABSTRACT FROM AUTHOR]

Activated carbons are one of the most important classes of high‐surface‐area porous materials. Owing to their unique structure, low price, and large‐scale production technology, these porous carbons have been traditionally used as sorbents for eliminating contamination. In the past decade, many innovations have been seen in the synthesis, structure, applications, and theoretical and experimental methods. Herein, a comprehensive review of the up‐to‐date progress of activated carbons is presented from the viewpoint of synthetic chemistry and materials science. First, the critical textural properties are discussed, with special emphasis on the porous texture, heteroatom doping, surface functional groups, and partial graphitization. Next, the advanced synthetic strategies of activated carbons are summarized. Special attention is given to the reaction mechanism between activating agents and carbon sources, as well as the design of controlled forms and morphology. Then, their applicability in various emerging fields is covered, including supercapacitors, capacitive deionization, batteries, electrocatalysis, and carbon capture. In particular, this review highlights the potential synthesis–structure–property correlations of these porous materials. Finally, we present the future challenges and outlook for their success in energy and environmental science. [ABSTRACT FROM AUTHOR]

Graphene fibers with integrated mechanical and multifunctional properties are highly required for various potential applications. However, it remains a challenge to efficiently produce high‐performance graphene fibers because of the imperfect structures and harsh graphitization conditions. Herein, a scalable additive‐free wet‐spinning methodology is demonstrated for producing strong, tough, and conductive pristine graphene fibers by optimizing the surface chemistry of graphene oxide (GO) sheets and controlling their spinning and assembly behavior. Benefiting from GO with fewer surface terminations and low structural defects (f‐GO), the pristine f‐GO fibers possess a compact and ordered microstructure and strong interlayer interactions, giving a record high tensile strength of 791.7 MPa and high toughness of 24.0 MJ m−3 due to the stretching‐induced toughening behavior. After the mild chemical reduction, reduced f‐GO fibers inherit the optimized microstructure and present an outstanding tensile strength of 875.9 MPa and high toughness of 13.3 MJ m−3. Furthermore, the repairable structural defects on the f‐GO sheets allow the instant restoration of intrinsic conjugated structures, affording a superb electrical conductivity of 1.06 × 105 S m−1. Therefore, this study provides a facile, efficient, and scalable methodology for the fabrication of high‐performance and multifunctional graphene fibers and flexible wearable devices. [ABSTRACT FROM AUTHOR]

Recently, developing matchable cathode materials of Zn ion hybrid capacitor still remains difficult owing to insufficient understanding of the charge storage behavior. However, most previous efforts are devoted to explain the effect of oxygen‐containing groups without paying attention to graphitic structure. Herein, the charge storage capability and electrochemical kinetics of reduce graphene oxide (rGO) nanosheets are optimized as a function of their surface properties. Beyond the contribution of oxygen‐containing groups, an extra contribution from the reversible adsorption/desorption of H+ on carbon atom of rGO sheets is confirmed. Electrochemical analysis and density functional theory calculations reveal that H+ induces disruption of π cloud in aromatic domain, accompanied by C sp2‐sp3 re‐hybridization and the distortion/restoration of graphitic structure. The optimal electrochemical performance with a specific capacitance of 245 F g‐1 at 0.5 A g‐1 with 53% retention at 20 A g‐1 is achieved for rGO thermally treated at 200 °C. As a proof‐of‐concept application, the 3D printed rGO electrode delivers a high areal capacitance of 1011 mF cm‐2 and an energy density of 266 μWh cm‐2. The study is believed to broaden the horizons of proton adsorption chemistry and shed light on the design of novel electrode materials. [ABSTRACT FROM AUTHOR]

Self‐organizing 2D sheets into a 3D structure with a well‐defined arrangement and tuned bandgap has garnered significant interest. However, there exist challenges such as scalable and feasible synthetic methods and preservation of 2D properties while preventing re‐stacking. Herein, a facile method for the mass production of 2D manifolds of graphene oxide (GO), which are 3D microtubes, while maintaining their 2D properties by applying shear to roll up GO sheets, is reported. The GO mesotubes are formed by shear flow in aluminum–glass parallel plates. Redox reaction plays a vital role during the formation of GO mesotubes by the vorticity alignment during slow shear flow. A high yield of 94% is achieved at an initial pH of 2.2. The maximum d‐spacing of the GO sheet in the tube wall is 21 nm, indicating no re‐stacking of the graphitic structure. It is demonstrated that the GO mesotubes behaves like a soft gel, rendering them a candidate material for soft robotics, e‐skins, and a visible light sensor owing to their reduced optical bandgap. [ABSTRACT FROM AUTHOR]

The development of earth‐abundant oxygen reduction reaction (ORR) catalysts with high catalytic activity and good stability for practical metal‐air batteries remains an enormous challenge. Herein, a highly efficient and durable ORR catalyst is reported, which consists of atomically dispersed Co single atoms (Co‐SAs) in the form of Co‐N4 moieties and small Co nanoparticles (Co‐SNPs) co‐anchored on nitrogen‐doped porous carbon nanocage (Co‐SAs/SNPs@NC). Benefiting from the synergistic effect of Co‐SAs and Co‐SNPs as well as the enhanced anticorrosion capability of the carbon matrix brought by its improved graphitization degree, the resultant Co‐SAs/SNPs@NC catalyst exhibits outstanding ORR activity and remarkable stability in alkaline media, outperforming Co‐SAs‐based catalyst (Co‐SAs@NC), and benchmark Pt/C catalyst. Density functional theory calculations reveal that the strong interaction between Co‐SNPs and Co‐N4 sites can increase the valence state of the active Co atoms in Co‐SAs/SNPs@NC and moderate the adsorption free energy of ORR intermediates, thus facilitating the reduction of O2. Moreover, the practical zinc‐air battery assembled with Co‐SAs/SNPs@NC catalyst demonstrates a maximum power density of 223.5 mW cm–2, a high specific capacity of 742 W h kg–1 at 50 mA cm–2 and a superior cycling stability. [ABSTRACT FROM AUTHOR]

The design and manufacture of advanced materials based on biomaterials provide new opportunities to solve many technological challenges. In this work, a highly graphitized wood framework (GWF) with a porous tunnel structure and microvilli is constructed as a multifunctional interlayer to improve the electrochemical performance of lithium–sulfur (Li–S) batteries. The GWF not only retains the 3D transport network of wood, but also offers increased deposition sites for polysulfides through the microvilli which grow on the inner surfaces of the carbon tunnels. Electrochemical tests show that GWF effectively enhances the initial discharge capacity of the Li–S battery to 1593 mAh g−1 at 0.05 C, with a low capacity decline of 0.06% per cycle at 1 C. Besides, the GWF interlayer also effectively protects lithium anodes from corrosion by Sx2−, thus they still keep their metallic luster and clean surface even after long charge‐discharge cycles. These enhancements are attributed to the high conductivity, abundant microvilli, and tunnel confinement effects of GWF, which effectively inhibit the shuttle effect of polysulfides by the same principle as nose hairs filtering the air. This work presents a new understanding of bionic/biomaterials and a new strategy to improve the performance of Li–S batteries. [ABSTRACT FROM AUTHOR]

Engineering the structure and chemistry of solid electrolyte interface (SEI) on electrode materials is crucial for rechargeable batteries. Using hard carbon (HC) as a platform material, a correlation between Na+ storage performance, and the properties of SEI is comprehensively explored. It is found that a "good" SEI layer on HC may not be directly associated with certain kinds of SEI components, such as NaF and Na2O. Whereas, arranging nano SEI components with refined structures constructs the foundation of "good" SEI that enables fast Na+ storage and interface stability of HC in Na‐ion batteries. A layer‐by‐layer SEI on HC with inorganic‐rich inner layer and tolerant organic‐rich outer flexible layer can facilitate excellent rate and cycling life. Besides, SEI layer as the gate for Na+ from electrolyte to HC electrode can modulate interfacial crystallographic structures of HC with pillar‐solvent that function as "pseudo‐SEI" for fast and stable Na+ storage in optimal 1 m NaPF6‐TEGDME electrolytes. Such a layer‐by‐layer SEI combined with a "pseudo‐SEI" layer for HC enables an outstanding rate of 192 mAh g−1 at 2 C and stable cycling over 1100 cycles at 0.5 C. This study provides valuable guidance to improve the electrochemical performance of electrode materials through regulation of SEI in optimal electrolytes. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMOs)‐based anode materials of high theoretical capacities have been intensively studied for lithium‐ion storage. However, their poor high‐rate capability and cycling stability remain to be effectively resolved. Herein, a novel ion exchange (IE)‐assisted indirect carbon coating strategy is proposed to realize high performance freestanding TMO‐based anodes for flexible lithium‐ion batteries (FLIBs). This approach effectively avoids the possible side reaction of oxide reduction, enhances degrees of graphitization of the carbon coating, and preserves advantageous nanostructure of the starting template, leading to enhanced electrical conductivities, alleviated volume variation induced structural instability, fast lithium‐ion diffusion pathways and enhanced electron transfer kinetics. As a proof of concept, IE‐prepared carbon coated NiO nanosheet arrays with excellent structural and electrochemical stability are developed as freestanding anodes for LIBs and FLIBs, which exhibit outstanding electrochemical performances superior to most state‐of‐the‐art NiO‐based anodes reported in recent years. The product anode delivers a high areal capacity (3.08 mAh cm−2 at 0.25 mA cm−2), outstanding high‐rate capability (1.78 mAh cm−2 at 8 mA cm−2) and excellent cycling stability (over 300 cycles). Further pouch cell tests confirm the excellent flexibility of the freestanding electrode against mechanical deformation with well‐maintained electrochemical performance under folding. [ABSTRACT FROM AUTHOR]

Designing copper (Cu) current collectors is a convenient way to stabilize lithium (Li) metal anodes. However, Cu current collectors and their derived Li/Cu anodes still face several obstacles, including lithiophobic and oxidizable Cu surface, cumbersome anode fabrication process, and low Li utilization. Here, a formate‐treatment strategy is presented to reconstruct Cu current collectors with a passivation layer covered Cu(110) surface. This method can easily be generalized to increase the lithiophilicity and oxidation resistibility of Cu current collectors. Using the formate‐treated Cu nanowire network as an anode current collector, the full cell consisting of a LiFePO4 cathode and Li/Cu anode with a low negative/positive capacity ratio delivers an excellent cycling performance with 74.8% capacity retention after 1000 cycles at 1 C. In addition, a concept of an upper current collector is introduced to simplify the manufacturing procedure of Li/Cu anodes. This work provides new insights into the design and construction of high‐performance Li/Cu anodes. [ABSTRACT FROM AUTHOR]

The rational design and facile synthesis of 1D hollow tubular carbon‐based materials with highly efficient oxygen reduction reaction (ORR) performance remains a challenge. Herein, a simple yet robust route is employed to simultaneously craft single‐atomic Fe sites and graphitic layer‐wrapped Fe3C nanoparticles (Fe3C@GL NPs) encapsulated within 1D N‐doped hollow mesoporous carbon tubes (denoted Fe‐N‐HMCTs). The successional compositional and structural crafting of the hydrothermally self‐templated polyimide tubes (PITs), enabled by Fe species incorporation and acid leaching treatment, respectively, yields Fe‐N‐HMCTs that are subsequently exploited as the ORR electrocatalyst. Remarkably, an alkaline electrolyte capitalizing on Fe‐N‐HMCTs achieves excellent ORR activity (onset potential, 0.992 V; half‐wave potential, 0.872 V), favorable long‐term stability, and strong methanol tolerance, outperforming the state‐of‐the‐art Pt/C catalyst. Such impressive ORR performances of the Fe‐N‐HMCTs originate from the favorable configuration of active sites (i.e., atomically dispersed Fe‐Nx sites and homogeneously incorporated Fe3C@GL NPs) in conjunction with the advantageous 1D hollow tubular architecture containing adequate mesoporous surface. This work offers a new view to fabricate earth‐abundant 1D Fe‐N‐C electrocatalysts with well‐designed architecture and outstanding performance for electrochemical energy conversion and storage. [ABSTRACT FROM AUTHOR]

Heteroatoms in the carbon matrix are generally considered as active sites to enhance potassium storage capacity, while their adverse effects on ion batteries remain unclear. Herein, a series of sulfur doped carbon (SCDPx) with adjustable S content and crystallinity are accurately synthesized in the closed autoclave by controlling the ratios of precursors. Electrochemical measurements exhibit that heteroatom sulfur displays double‐edged electrochemical activities with a high initial potassium storage capacity but poor cycling stability for carbon anode. Combined with solid‐state nuclear magnetic resonance (NMR), catalytic tests, and various ex‐situ characterizations, it is demonstrated that abundant S in the carbon would not only form CSC bonds, acting as active sites to reversibly adsorb/desorb potassium ions for high capacity, but also significantly catalyze the reduction and decomposition of the electrolyte including KPF6 and ethylene carbonate/diethyl carbonate (EC/DEC) to form thicker solid electrolyte interface (SEI) and degrade electrolyte, resulting in rapid capacity decay. As a result, the optimized sample (SCDP2) with the appropriate sulfur doping content exhibits the best electrochemical performance with high capacity (688.4 mA h g−1 at 100 mA g−1), long‐term cycling stability (198.4 mA h g−1 at 2000 mA g−1 after 10 000 cycles), and excellent rate capability (238.8 mA h g−1 at 5000 mA g−1). [ABSTRACT FROM AUTHOR]

Doping carbon materials with p‐block elements such as nitrogen is an effective approach to tune electronic properties of the framework and can endow the host's new characters. To date, highly doped carbons with tunable nitrogen speciation are still less explored due to the grand challenge in fabrication; for example, the typical synthesis based on the pyrolysis of nitrogen‐containing precursors shows a trade‐off between the total nitrogen content and the carbonization temperature, limiting the value to ≈12 wt% at 1073 K. Herein, intensifying ring opening of cross‐linked polymers through controlled pre‐oxidation followed by conventional pyrolysis is demonstrated as an elegant method to circumvent this challenge. In addition to fine tunability at different nitrogen speciation, this strategy can increase the nitrogen content by two‐ to threefold (maximum ≈22 wt%) and shows general viability in six different N‐bearing (co)polymers. The highly doped pyridinic nitrogen‐rich carbons show i) a remarkable capacity of 879 mAh g−1 at 0.1 A g−1 and excellent cycling performance in lithium ion batteries, and ii) significantly boosted catalytic performance in the selective oxidation of diverse substrates. Therefore, this facile synthetic strategy and the tunability at nitrogen functionalities will greatly broaden the applications of this new class of functional materials. [ABSTRACT FROM AUTHOR]

High‐energy‐density Li–S batteries are considered one of the next‐generation energy storage systems, but the uncontrolled Li‐dendrite growth in Li metal anodes and the shuttling of polysulfides in S cathode severely impede the commercial development of Li–S batteries. Herein, a conductive composite architecture that is made up of bio‐derived N‐doped porous carbon fiber bundles (N‐PCFs) with co‐imbedded cobalt and niobium carbide nanoparticles is employed as a multifunctional integrated host for simultaneously addressing the challenges in both Li anodes and S cathodes. The implantation of Co and NbC nanoparticles bestows the N‐PCFs matrix with synergistically enhanced degree of graphitization, electrical conductivity, hierarchical porosity, and surface polarization. Theoretical calculations and experimental results show that NbC with specific lithiophilic and sulfiphilic features can synchronously regulate the Li and S electrochemistry by realizing homogeneous lithium deposition with suppressed Li‐dendrite growth and exerting catalytic effects for promoting the polysulfide conversion together with fast Li2S nucleation. Hence, the assembled Li–S full batteries exhibit a superb rate capability (704 mAh g−1 at 5 C) and cycling life (≈82.3% capacity retention after 500 cycles) at a sulfur loading over 3.0 mg cm−2, as well as high reversible areal capacity (>6.0 mAh cm−2) even at a higher sulfur loading of 6.7 mg cm−2. [ABSTRACT FROM AUTHOR]

To enhance the performance of Li‐ion batteries, hierarchical carbon‐based hollow frameworks embedded with cobalt nanoparticles are prepared by the pyrolysis of core‐shell ZIF‐8@ZIF‐67 polyhedrals prepared via a seed‐mediated growth method. The resultant hollow frameworks are composed of the N‐doped carbon as the inner shells and the porous graphitic carbon embedded with cobalt nanoparticles as the outer shells. Benefiting from the unique hollow architecture with large surface area and good electrical conductivity, the electrode materials exhibit good electrochemical performance with improved specific capacities, high‐rate capability, and good cycling stability for Li‐ion batteries. More importantly, the quantitative kinetic analysis reveals the crucial contributions of N doping and the porous structure of graphitic carbon with cobalt nanoparticles for boosting the performance of carbon‐based materials. The rational design of the unique carbon‐based architecture and the understanding of the underlying mechanism for the charge storage process are crucial to construct advanced carbon‐based materials for high‐performance Li‐ion batteries. [ABSTRACT FROM AUTHOR]

The construction of 3D graphitic structures can lead to many important scientific study and nanotechnology applications, but its widespread use can be limited by the narrow van der Waals gap (vdW; <0.35 nm). Here, this study reports the use of natural adsorbent organisms to engineer the expanded graphitic structure. It shows that, in chitosan, the abundant amino (NH2) and hydroxyl (OH) groups can act as metal ions "pitfalls" for the growth of catalytic transition‐metal crystals under thermally reductive conditions. In situ transmission electron microscopy study reveals the "liquidized" migration process of Ni carbide crystal that catalyzes the graphitization of 3D carbon network and enables the expansion of vdW gaps. A correlation between the thermodynamically trapped metal atoms and the expansion of vdW gaps is established by expanding the study to both Co and Cu. The findings provide insights into new strategy to be explored for engineering 3D carbon‐based materials and show significant potential in energy storage and catalysis technologies. [ABSTRACT FROM AUTHOR]

Graphdiyne (GDY), an emerging type of carbon allotropes, possesses fascinating electrical, chemical, and mechanical properties to readily spark energy applications in the realm of Li‐ion and Na‐ion batteries. Nevertheless, rational design of GDY architectures targeting advanced K‐ion storage has rarely been reported to date. Herein, the first example of synthesizing GDY frameworks in a scalable fashion to realize superb potassium storage for high‐performance K‐ion battery (KIB) anodes is showcased. To begin with, first principles calculations provide theoretical guidances for analyzing the intrinsic potassium storage capability of GDY. Meanwhile, the specific capacity is predicted to be as high as 620 mAh g−1, which is considerably augmented as compared with graphite (278 mAh g−1). Experimental tests then reveal that prepared GDY framework indeed harvests excellent electrochemical performance as a KIB anode, achieving high specific capacity (≈505 mAh g−1 at 50 mA g−1), outstanding rate performance (150 mAh g−1 at 5000 mA g−1) and favorable cycling stability (a high capacity retention of over 90% after 2000 cycles at 1000 mA g−1). Furthermore, kinetic analysis reveals that capacitive effect mainly accounts for the K‐ion storage, with operando Raman spectroscopy/ex situ X‐ray photoelectron spectroscopy identifying good electrochemical reversibility of GDY. [ABSTRACT FROM AUTHOR]

The fabrication of sulfur‐containing carbonaceous anode materials (CS) that show exceptional activity as anode material in Na‐ions batteries is reported. To do so, a general and straightforward bottom‐up synthesis of CS materials with precise control over the sulfur content and functionality is introduced. The new synthetic path combined with a detailed structural analysis and electrochemical studies provide correlations between i) the sulfur content and chemical species and ii) the structural, electronic, and electrochemical performance of the associated materials. As a result, the new CS substances demonstrate excellent activity as Na‐ion battery anode materials, reaching capacity values above 500 mAh g−1 at a current density of 0.1 A g−1, as well as high reversible sodium storage capabilities and excellent cycling durability. The results reveal the underlying working principles of carbonaceous materials, alongside the storage mechanism of the Na+ ions in these advanced sodium‐ion battery anode materials and provide a new avenue for their practical realization. [ABSTRACT FROM AUTHOR]

Porous carbon materials have demonstrated exceptional performance in a variety of energy‐ and environment‐related applications. Over the past decades, tremendous efforts have been made in the coordinated design and fabrication of porous carbon nanoarchitectures in terms of pore sizes, surface chemistry, and structure. Herein, structure‐oriented carbon design and applications are reviewed. The unique properties of porous carbon materials that offer them promising design opportunities and broad applicability in some representative fields, including water remediation, CO2 capture, lithium‐ion batteries, lithium–sulfur batteries, lithium metal anodes, Na‐ion batteries, K‐ion batteries, supercapacitors, and the oxygen reduction reaction are highlighted. Then, the most up‐to‐date strategies for structural control and functionalization of porous carbons are summarized, toward tailoring microporous, mesoporous, macroporous, and hierarchically porous carbons with disordered or ordered, amorphous or graphitic structures. Meanwhile, the emerging features of these structures in various applications are introduced where applicable. Finally, insights into the challenges and perspectives for future development are provided. [ABSTRACT FROM AUTHOR]

Hard carbons are among the most promising materials for alkali‐ion metal anodes. These materials have a highly complex structure and understanding the metal storage and migration within these structures is of utmost importance for the development of next‐generation battery technologies. The effect of different carbon structural motifs on Li, Na, and K storage and diffusion are probed using density functional theory based on experimental characterizations of hard carbon samples. Two carbon structural models—the planar graphitic layer model and the cylindrical pore model—are constructed guided by small‐angle X‐ray scattering and transmission electron microscopy characterization. The planar graphitic layers with interlayer distance <6.5 Å are beneficial for metal storage, but do not have significant contribution to rapid metal diffusion. Fast diffusion is shown to take place in planar graphitic layers with interlayer distance >6.5 Å, when the graphitic layer separation becomes so wide that there is negligible interaction between the two graphitic layers. The cylindrical pore model, reflecting the curved morphology, does not increase metal storage, but significantly lowers the metal migration barriers. Hence, the curved carbon morphologies are shown to have great importance for battery cycling. These findings provide an atomic‐scale picture of the metal storage and diffusion in these materials. [ABSTRACT FROM AUTHOR]

Using synergetic effects of various sodium storage modes and materials to construct high power, high energy, and long cycling flexible sodium anode materials is significant and still challenging. Here, by advantageous functional integration of adsorption‐intercalation‐conversion sodium storage mechanisms, a 3D flexible fiber paper anode with the composition of Nb2O5@hard carbon@MoS2@soft carbon is designed and prepared. Based on the synergetic effects, it exhibits higher specific capacity than pure Nb2O5, with more excellent rate performance (245, 201, 155, 133, and 97 mAh g−1 at the current density of 0.2, 1, 5, 10, and 20 A g−1, respectively) than pure MoS2 as well as admirable long‐term cycling characteristics (≈82% capacity retention after 20 000 cycles at 5 A g−1). Relevant kinetics mechanisms are expounded in detail. This work can be helpful for preparing other types of hybrid and flexible electrodes for energy storage systems. [ABSTRACT FROM AUTHOR]

Silicon (Si) and lithium metal are the most favorable anodes for high‐energy‐density lithium‐based batteries. However, large volume expansion and low electrical conductivity restrict commercialization of Si anodes, while dendrite formation prohibits the applications of lithium‐metal anodes. Here, uniform nanoporous Si@carbon (NPSi@C) from commercial alloy and CO2 is fabricated and tested as a stable anode for lithium‐ion batteries (LIBs). The porosity of Si as well as graphitization degree and thickness of the carbon layer can be controlled by adjusting reaction conditions. The rationally designed porosity and carbon layer of NPSi@C can improve electronic conductivity and buffer volume change of Si without destroying the carbon layer or disrupting the solid electrolyte interface layer. The optimized NPSi@C anode shows a stable cyclability with 0.00685% capacity decay per cycle at 5 A g−1 over 2000 cycles for LIBs. The energy storage mechanism is explored by quantitative kinetics analysis and proven to be a capacitance‐battery dual model. Moreover, a novel 2D/3D structure is designed by combining MXene and NPSi@C. As lithiophilic nucleation seeds, NPSi@C can induce uniform Li deposition with buffered volume expansion, which is proven by exploring Li‐metal deposition morphology on Cu foil and MXene@NPSi@C. The practical potential application of NPSi@C and MXene@NPSi@C is evaluated by full cell tests with a Li(Ni0.8Co0.1Mn0.1)O2 cathode. [ABSTRACT FROM AUTHOR]

Abstract: A facile approach for the template‐free synthesis of highly active non‐noble metal based oxygen reduction reaction (ORR) electrocatalysts is presented. Porous Fe−N−C/Fe/Fe3C composite materials are obtained by pyrolysis of defined precursor mixtures of polyformamidine (PFA) and FeCl3 as nitrogen‐rich carbon and iron sources, respectively. Selection of pyrolysis temperature (700–1100 °C) and FeCl3 loading (5–30 wt%) yields materials with differing surface areas, porosity, graphitization degree, nitrogen and iron content, as well as ORR activity. While the ORR activity of Fe‐free materials is limited (i.e., synthesized from pure PFA), a huge increase in activity is observed for catalysts containing Fe, revealing the participation of the metal dopant in the construction of active electrocatalytic sites. Further activity improvement is achieved via acid‐leaching and repeated pyrolysis, a result which is attributed to the creation of new active sites located at the surface of the porous nitrogen‐doped carbon by dissolution of the Fe and Fe3C nanophases. The best performing catalyst, which was synthesized with a low Fe loading (i.e., 5 wt%) and at a pyrolysis temperature of 900 °C, exhibits high activity, excellent H2O selectivity, extended stability, in both basic and acidic media as well as a remarkable tolerance toward methanol. [ABSTRACT FROM AUTHOR]

A vertically aligned carbon nanofiber (VACNF) array with unique conically stacked graphitic structure directly grown on a planar Cu current collector (denoted as VACNF/Cu) is used as a high‐porosity 3D host to overcome the commonly encountered issues of Li metal anodes. The excellent electrical conductivity and highly active lithiophilic graphitic edge sites facilitate homogenous coaxial Li plating/stripping around each VACNF and forming a uniform solid electrolyte interphase. The high specific surface area effectively reduces the local current density and suppresses dendrite growth during the charging/discharging processes. Meanwhile, this open nanoscale vertical 3D structure eliminates the volume changes during Li plating/stripping. As a result, highly reversible Li plating/stripping with high coulombic efficiency is achieved at various current densities. A low voltage hysteresis of 35 mV over 500 h in symmetric cells is achieved at 1 mA cm−2 with an areal Li plating capacity of 2 mAh cm−2, which is far superior to the planar Cu current collector. Furthermore, a Li–S battery using a S@PAN cathode and a lithium‐plated VACNF/Cu (VACNF/Cu@Li) anode with slightly higher capacity (2 mAh cm−2) exhibits an excellent rate capability and high cycling stability with no capacity fading over 600 cycles. [ABSTRACT FROM AUTHOR]

Stretchable/wearable strain sensors are attracting growing interest due to their broad applications in physical and physiological measurements. However, the development of a multifunctional highly stretchable sensor satisfying the requirements of ultrahigh sensitivity (able to distinguish sound frequency) remains a challenge. An ultrasensitive and highly stretchable multifunctional strain sensor with timbre‐recognition ability based on high‐crack‐density vertical graphene (VGr) is fabricated using an ultrasonic peeling (UP) method. It can distinguish frequencies of sounds higher than 2500 Hz. Detailed microscopic examinations reveal that their ultrahigh sensitivity stems from the formation of high‐density nanocracks in the graphitic base layer, which is bridged by the top branched VGr nanowalls. These nanocracks cut the VGr film into a large number of nanopieces, which increase the natural frequency of the sensors, enabling the sensors to distinguish the sound frequency. Demonstrations are presented to highlight the sensors' potential as wearable devices for human physiological signal and timbre detections. This is the first multifunctional highly stretchable strain sensor with timbre‐recognition ability. [ABSTRACT FROM AUTHOR]

Single atomic Fe–Nx moieties embedded on a high surface area carbon (Fe–N/C) represents one of the most promising nonprecious metal electrocatalysts for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells. While significant progress has been made in the preparation of Fe–N/C catalysts with high‐density Fe–Nx sites, key structural descriptors determining the intrinsic activity of the Fe center remain elusive, and effective ways to enhance the intrinsic activity are still lacking. Moreover, most Fe–N/C catalysts developed to date are built on carbons with rather low graphitization degree, which suffer from relatively severe carbon corrosion and thereby poor stability. The direct growth of carbon nanotubes doped with high‐density Fe–Nx sites neighbored with graphitic‐nitrogen‐rich environment is reported here, which are successfully applied as a both active and stable ORR electrocatalyst in fuel cells. Combining both experiments and density functional theory calculations, it is revealed that the neighboring graphitic nitrogen can effectively induce higher filling degree of d‐orbitals and simultaneously decrease on‐site magnetic moment (namely, lowered spin) of the Fe center, which can optimize the binding energies of ORR intermediates and thereby substantially enhance intrinsic ORR activity. [ABSTRACT FROM AUTHOR]

Carbon‐based materials are promising anodes for potassium‐ion batteries (PIBs). However, due to the significant volume expansion and structural instability, it is still a challenge to achieve a high capacity, high rate and long cycle life for carbonaceous anodes. Herein, oxygen/fluorine dual‐doped porous carbon nanopolyhedra (OFPCN) is reported for the first time as a novel anode for PIBs, which exhibits a high reversible capacity of 481 mA h g−1 at 0.05 A g−1 and excellent performance of 218 mA h g−1 after 2000 cycles at 1 A g−1 with 92% capacity retention. Even after 5000 robust cycles at 10 A g−1 with charging/discharging time of around 40 s, an unprecedented capacity of 111 mA h g−1 is still maintained. Such ultrafast potassium storage and unprecedented cycling stability have been seldom reported in PIBs. Quantitative kinetics analysis reveals that both diffusion and capacitance processes are involved in the potassium storage mechanism. Density functional theory calculations demonstrate that the O/F dual‐doped porous carbon promotes the K‐adsorption ability and can absorb multiple K atoms with slight structural distortion, which accounts for the high specific capacity, outstanding rate capability, and excellent cycling stability of the OFPCN anode. [ABSTRACT FROM AUTHOR]

Given that the performance of a lithium–oxygen battery (LOB) is determined by the electrochemical reactions occurring on the cathode, the development of advanced cathode nanoarchitectures is of great importance for the realization of high‐energy‐density, reversible LOBs. Herein, a robust cathode design is proposed for LOBs based on a dual‐phasic carbon nanoarchitecture. The cathode is composed of an interwoven network of porous metal–organic framework (MOF) derived carbon (MOF‐C) and conductive carbon nanotubes (CNTs). The dual‐phasic nanoarchitecture incorporates the advantages of both components: MOF‐C provides a large surface area for the oxygen reactions and a large pore volume for Li2O2 storage, and CNTs provide facile pathways for electron and O2 transport as well as additional void spaces for Li2O2 accommodation. It is demonstrated that the synergistic nanoarchitecturing of the dual‐phasic MOF‐C/CNT material results in promising electrochemical performance of LOBs, as evidenced by a high discharge capacity of ≈10 050 mAh g−1 and a stable cycling performance over 75 cycles. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) have triggered considerable attention as candidates for solar‐thermal energy conversion. However, their intrinsic low thermal conductivity prevents the rapid spreading of heat into the interior of the PCM, causing low efficiencies in energy storage/release. Herein, anisotropic and lightweight high‐quality graphene aerogels are developed by directionally freezing aqueous suspensions of polyamic acid salt and graphene oxide to form vertically aligned monoliths, followed by freeze‐drying, imidization at 300 °C and graphitization at 2800 °C. After impregnating with paraffin wax, the resultant phase change composite (PCC) exhibits a high transversal thermal conductivity of 2.68 W m−1 K−1 and an even higher longitudinal thermal conductivity of 8.87 W m−1 K−1 with an exceptional latent heat retention of 98.7%. When subjected to solar radiation, solar energy is converted to heat at the exposed surface of the PCC. As a result of the PCC's high thermal conductivity in the thickness direction, heat can spread readily into the interior of the PCC enabling a small temperature gradient of <3.0 K cm−1 and a fast charging feature. These results demonstrate the potential for real‐time and fast‐charging solar‐thermal energy conversion using phase change materials with tailored anisotropy in their thermal properties. Anisotropic and high‐quality graphene aerogels are fabricated by directional‐freezing of polyamic acid salt/graphene oxide slurries, followed by freeze‐drying, imidization, and graphitization. A phase change composite derived from the aerogel exhibits both high longitudinal thermal conductivity of ≈8.87 W m−1 K−1 and excellent latent heat retention of 98.7% with satisfactory stability, and is suitable for real‐time and fast solar‐thermal energy conversion. [ABSTRACT FROM AUTHOR]