Electron Conductivity Research Articles

Electron and hole bipolar injection in magnesium oxide films

It is assumed that the reliability and functionality of nonvolatile memory elements based on MgO are determined by the charge transport in MgO. In the present study, the type of MgO conductivity is established using experiments on the injection of minority charge-carriers in the n(p)-Si/MgO/Mg structures. It is shown that electrons and holes contribute to the MgO conductivity, causing bipolar charge transport. Using ab initio simulations, it was found that native point defects in MgO can provide both electron and hole conductivity.

Electronic transport of an extended Ising chain with competing thermal fluctuation and magnetic ordering

In this study, we investigate the behavior of spin-dependent electronic transport in a magnetic nanowire with thermal random oriented moments, connected to two similar (anti-) ferromagnetic leads. The model is based on Green’s function technique within the nearest neighbor tight-binding approach in the framework of canonical ensemble. We analyze the electronic transmission and its variance in different ordered and disordered regimes at a finite temperature in an external magnetic field. The results indicate that at nonzero temperatures, thermal fluctuation of moment orientations decreases the system’s electronic conductance, leading to a smooth conductance-energy relationship. Depending on temperature and external magnetic field values as well as Ising exchange interaction strength, the system can transit to an ordered phase. Additionally, the larger length of the interacting part affects the transmission coefficient and amplifies its variance. This study sheds light on the intricate interplay between temperature, magnetic field, and moment orientations in the context of spin-dependent electronic transport through magnetic nanowires, offering valuable insights into the usage of such systems.

Achieving long-life and efficient sodium storage through encapsulating Fe3Se4 nanoparticles within hollow mesoporous carbon nanospheres

The application of Fe3Se4 in sodium-ion batteries is limited due to its poor cycling performance and inferior rate capability. Herein, we employ a multi-step process, involving solution adsorption, molten adsorption, calcination and gaseous selenization, to encapsulate Fe3Se4 nanoparticles within monodispersed hollow mesoporous carbon nanospheres (Fe3Se4@HMCN). The space-confined effect of HMCNs refines Fe3Se4 nanoparticles, compelling Fe3Se4 to adhere to the internal wall of HMCNs. In half-cells, Fe3Se4@HMCN exhibits remarkable rate capability at current densities of 0.1–10 A g−1, and exceptional cycling performance (525 mAh g−1 at 1.0 A g−1 after 400 cycles, 282 mAh g−1 at 5.0 A g−1 after 1800 cycles, 204 mAh g−1 after 2000 cycles at 10.0 A g−1), surpassing both pure HMCNs and bare Fe3Se4. The composite structure significantly improves Na storage performance of Fe3Se4, while Fe3Se4 also contributes the majority of the capacity of the composite. Kinetic studies further unveil rapid Na+ transport, low reaction impedance and a predominant pseudocapacitive effect. In Fe3Se4@HMCN//Na3V2(PO4)3 full cell, Fe3Se4@HMCN sustains a discharge capacity of 175 mAh g−1 after 1200 cycles at 5.0 A g−1. The superior electrochemical performance is attributed to the nanoencapsulation structure based on HMCNs, which synergistically enhances electron conduction, ion transport and structural stability of Fe3Se4.

Fe-doping on CaV2O6 for oxygen vacancy controlling lithium storage

Currently, alkaline earth metal vanadates as the anode materials for lithium-ion batteries (LIBs) are gradually sparking attention due to their low cost, environmental friendliness, high theoretical capacity and safety. However, their practical application is still hampered by the fast capacity degradation resulting from the prolonged cycling condition and intrinsic low electrical conductivity. Herein, single-crystal Fe-doped CaV2O6 is prepared via the low-temperature combustion synthesis route. The Fe-doping accelerates the generation of low-valence-state vanadium in CaV2O6–2%Fe, leading to the production of oxygen vacancies for maintaining electroneutrality. The versatile design of CaV2O6–2%Fe improves the electron conductivity and promotes the Li-ion diffusion rate based on the generated dual defects of interstitial atoms of Fe and oxygen vacancies accordingly. As expected, the CaV2O6–2%Fe electrode exhibits superior rate capacity of 96.6 mA h g−1 at 5 A g−1 and a remarkable capacity retention of 125.6 mA h g−1 after 1000 cycles at 1 A g−1. Additionally, the partial decomposition of CaV2O6 during the initial lithiation stage, and the formation of amorphous Li–V–O in the subsequent cycle can be used to depict the lithium storage mechanism of CaV2O6–2%Fe.

Improvement of the ability of graphene by simultaneous cobalt (Co) and nitrogen (N) doping as an electrode for supercapacitor application

Thanks to its high electronic conductance and large surface, many research studies have investigated the application of graphene (Gr) in supercapacitors as an electrode material. The properties of Gr can change efficiently through the doping of specific elements and by designing various morphologies. In the current piece of research, DFT calculations are undertaken to investigate the impact of doping cobalt (Co) and nitrogen (N) atoms, and a monovacancy (MV)-added Gr structure upon the quantum capacitance (QC), electronic attributes and stability. Based on the calculations, doping Co and N and the presence of the MV radically changed the QC of the electrode. Nevertheless, achieving structural stability can be a challenge. A high QC of ∼77 μF/cm2 was obtained in the CoN3 system by the association of N-doping and the existence of the MV. The present piece of research provides insights into the viable impact of combined doping upon increasing the QC of Gr-based electrodes.

On the Influence of Li3InCl6−PEDOT:PSS Hybrids in Solid‐State Batteries Prepared via an Aqueous One‐Pot Approach

AbstractSolid‐state batteries (SSBs) utilizing halide solid electrolytes (SE) have garnered attention due to their enhanced stability when paired with oxide‐based cathode active materials. However, the dynamic interparticle contact during cycling in SSBs poses challenges to their stability and performance. To mitigate this problem, in this study, we present a one‐pot, aqueous synthesis of composites that integrate ion conductivity, electron conductivity, and mechanical stability into a single material. The developed composites consist of a halide SE, lithium indium chloride (Li3InCl6), and a conductive polymer (CP), poly(3,4‐ethylendioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS). The successful synthesis was verified using spectroscopic, thermal, scattering, and microscopy methods, with Kelvin Probe Force Microscopy (KPFM) demonstrating the distribution of PEDOT:PSS at the grain boundaries between Li3InCl6 particles. Upon incorporating our composite material with lithium nickel manganese cobalt oxide (NMC) cathode active material (CAM) as catholyte, an increase in the partial electronic transport was observed with increasing CP content. A direct correlation between the partial electronic transport of the catholytes and the initial discharge capacities was demonstrated. This study lays the groundwork for the preparation of multi‐functional catholytes under more sustainable conditions, without the need for organic solvents, extremely high temperatures, or special environments.

Encapsulation of Er-doped GeO2 nanofilms by Al2O3 atomic layers: Surficial sensitivity to trimethylaluminum and improvement on electroluminescence

Based on previous results of the Er-doped GeO2 nanofilms fabricated by atomic layer deposition (ALD), the interfacial reactions of Al2O3 precursor within the GeO2/Al2O3:Er nanolaminates are investigated. The ALD pulse of Al(CH3)3 etches the as-deposited GeO2 nanofilm, while the oxidation of Al(CH3)3 by ozone realizes the deposition of atomic Al2O3 layer onto GeO2 surface. The Al2O3 atomic layers with ≥4 ALD cycles improve the thermal stability of the ALD GeO2 nanofilms, which restrain the formation of nanograins and also the reduction of film thickness during high-temperature annealing, giving rise to smooth GeO2/Al2O3:Er nanolaminates. For the 1530 nm electroluminescence (EL) from the silicon-based devices fabricated using the GeO2/Al2O3:Er nanolaminates annealed at 800 °C, the excitation efficiency is tripled to 22.1 %. The conduction of the energetic electrons resulting in the EL emissions still confirms to the trap-assisted tunneling mechanism within these amorphous GeO2/Al2O3:Er nanolaminates. The prototype devices based on the Al2O3-inserted nanolaminates exhibit comparatively increased operation time. These GeO2/Al2O3:Er nanolaminates with enhanced stability and improved optoelectronics performance pave the way for the practical utilization of ALD GeO2 nanofilms.

P-doped hard carbon material for anode of sodium ion battery was prepared by using polyphosphoric acid modified petroleum asphalt as precursor

The practical value of hard carbon anode in sodium ion batteries has garnered significant attention. Asphalt-derived hard carbon offers lower cost and scale advantages compared to expensive resin and bio-based hard carbon materials. However, the synthesis of asphalt-derived hard carbon with significantly enhanced reversible capacity remains challenging. This study focuses on synthesizing P-doped hard carbon material using polyphosphoric acid-modified petroleum asphalt as a precursor and the pre-oxidation method. Doping P elements in hard carbon induces deformation of the molecular layer structure within the pseudo-graphite domains, expanding graphite layer spacing and increasing the number of internal closed micropores, thereby enhancing the sodium storage capacity of the matrix. The reversible capacity of P-doped hard carbon (PHC-1300) increased from 240.3 mA h g−1 to 359.9 mA h g−1 during the initial charge-discharge cycle at a rate of 0.05 C compared to undoped hard carbon (HC-1300). Moreover, phosphate exhibits higher reduction ability than adjacent carbon atoms, generating electron holes that partially compensate for limited electron conduction capability in hard carbon material. The electronic conductivity of the material increases from 26.1114 S cm−1 to 36.6418 S cm−1, demonstrating a significant enhancement compared to high graphitized soft carbon (SC-1300).Therefore, the practical significance of employing this straightforward precursor modification method to prepare P-doped hard carbon warrants attention.

Flexible thermoelectrics in crossed graphene/hBN composites

Nanostructures exhibit unusual properties due to the dominance of quantum mechanical effects. In addition, the geometry of a nanostructure can have a strong influence on its physical properties. Using the tight-binding and force-constant approaches with the help of the non-equilibrium Green’s function method, the transport and thermoelectric properties of cross-shaped (X-shaped) composite heterostructures are studied in two cases: Mixed graphene and h-BN (HETX-CBN) and all graphene (HETX-C) cross-shaped structures. Our numerical results show that an X-shaped structure helps to manipulate its electronic and phononic properties. The transport energy gap can be tuned in the range of ~ 0.8 eV by changing one arm width. Due to the drastic decrease in the electronic conductance of HETX-CBN and the dominance of the phononic thermal conductance, the ZT performance is degraded despite the high Seebeck coefficient value (in the order of meV). However, HETX-C has better ZT performance due to better electronic conductance and lower phononic/electronic thermal ratio, it can enhance the ZT ~ 2.5 times compared to that of zigzag graphene nanoribbon. The thermoelectric properties of the system can be tuned by controlling the size of the arms of the device and the type of its atoms.

Dielectric characterisation of chitosan-based composite membranes containing fractionated kraft and organosolv lignin

Chitosan-based composite membranes with fractionated kraft and organosolv lignin were prepared by solvent casting. A small lignin fraction (1%) was added to the neat chitosan to obtain a good distribution. The influence of lignin extraction with ethyl acetate and consequently ethanol on the dielectric and conductive properties of the composites was investigated by dielectric thermal analysis (DETA). Overall, the chitosan-lignin composites exhibit three relaxation mechanisms (β, βwet, and α) and two conductivity phenomena (σ and MWS). FTIR analysis showed that the composites with organosolv lignin fractions have fewer hydroxyl groups than those with kraft lignin, which decreases slightly further for both after ethanol extraction. The lignin fractions with lower molecular weight and higher OH content show stronger interactions with chitosan, due to hydrogen bonding. These interactions affect the thermal activation and cooperativity of the β-, βwet, and α-relaxation. Furthermore, the kraft lignin fractions with many polar groups are very compatible with the chitosan matrix, resulting in a more compact structure and higher fragility. The membranes CS OLEA and CS KLE have a lower electron conductivity and a higher proton conductivity. Thus, they have promising conductivity properties for fuel cell applications.

Catalytic Ozonation of Air toward Direct Nitric Acid Production Using Hierarchical Co3O4 with a Tunable Microstructure.

The nitrogen oxidation reaction (NOR) to form nitric acid by applying natural air and H2O under ambient conditions is a sustainable approach to achieving efficient and selective N2 fixation for industrial applications. In this study, four kinds of Co3O4 catalysts with a controllable microstructure were prepared to catalyze the direct NOR of N2 in the air. At the same time, the reaction mechanism of the conversion of N2 to nitric acid under catalytic ozonation was explored through experimental research and density functional theory (DFT) calculation. The results showed that the prepared porous nanosheets self-assembled into microflower-structured samples. The HCOF showed extraordinary catalytic performance for direct NOR to produce a high concentration of nitric acid. The maximum rate of nitric acid formation could be as high as 6.67 mmol/(h·gcat), which was higher than those of most reported photocatalytic or electrocatalytic N2 fixation processes for direct NOR to produce NO3-. Furthermore, the 15N isotopic-labeling experiment confirmed that the produced NO3- originated from N2 in the air by the direct NOR process. In the direct NOR mechanism, inert N2 molecules were captured at the Co3+ active sites by the acceptance-donation electron conduction mode, and the oxygen vacancies boosted the chemical adsorption of N2 molecules and greatly reduced the activation energy barrier of N2 molecules. The active free radicals •OH and •O2- generated by the decomposition of O3 molecules oxidized N2 to the intermediate *NO, which was the rate-determining step, and it was then absorbed by water to form nitric acid. The air catalytic ozonation method in this study was proposed as a facile pathway for efficient nitrogen fixation. This research provides a new method for environmental protection and efficient production of nitric acid at distributed sources.

Porous Magnesium Hydride Nanoparticles Uniformly Coated by Mg‐Based Composites toward Advanced Lithium Storage Performance

Magnesium hydride (MgH2) has been recognized as a promising anode material of lithium‐ion batteries (LIBs) owing to its ultrahigh specific capacity. The low conductivity and the structural pulverization induced by large volume expansion, however, has long limited its practical lithium storage performance. Herein, a series of yolk‐shell‐like structures, composed of porous MgH2 nanoparticles (NPs) decorated with Mg‐based composites through in‐situ solid‐gas reaction using MgH2 as both the reactant and the structural template, have been fabricated and uniformly dispersed on electronically conductive graphene. It could not only physically accommodate the volume change of MgH2 owing to the physical protection of Mg‐based composites and the formation of void space inside MgH2 NPs, but also effectively facilitate the transportation of electrons throughout the whole electrode. Particularly, the uniform decoration of ultrathin Mg(BH4)2 as the shell with thermodynamically favorable intercalation of lithium ions and low kinetic barrier for the lithium‐ion diffusion promotes facile transportation of lithium ions into active MgH2, which, coupled with the porous structure constructed by flexible graphene, effectively improves the ion conductivity of the electrode. The synergistic improvement in electronic and ionic conductivity leads to a high reversible capacity of 1651 mAh g−1 at 200 mA g−1 after 380 cycles.

NiS/Ni3S4 decorated double-layered hollow carbon spheres for efficient electrochemical hydrogen evolution reaction and supercapacitor

NiS/Ni3S4 anchored on the double-layer hollow carbon spheres (DLHCs@NixSy) were rationally conceived and synthesized via calcination and hydrothermal process. A series of characterization results confirmed nickel sulfide consisted of NiS and Ni2S3 phases formed. Double-layer hollow carbon spheres as substrates with good electrical conductivity, high specific surface area and hollow structure, not only serve as the active sites for nickel sulfide targeting and electron conduction, but also adapt to the volume change on cycling. Sample DLHCs@NixSy-1:2 prepared using optimized conditions exhibited enhanced electrochemical performance and energy storage in electrocatalytic hydrogen evolution and supercapacitor, respectively. The hybrid nanostructure just needed to afford the potential of 263 mV to reach the current density of 10 mA cm−2 without IR correction and delivered a high specific capacitance of 1160 F g−1 at a current density of 1 A g−1. Encouragingly, the asymmetric supercapacitor device created using DLHCs@NixSy-1:2 and active carbon exhibited a high energy density of 40 Wh/kg at 375 W/kg within the voltage window of 0–1.5 V. Furthermore, the device revealed preeminent cycling performance with a retention rate of 70 % after 2000 cycles at 4 A g−1. This result provided a reference for the synthesis of dual-functional materials with low cost and high efficiency.

Three-dimensional dual-layered conductive binder enables stable and high performance of SiOx/C anodes

Among practical anode materials for next-generation lithium-ion batteries (LIBs), SiOx has garnered substantial attention owing to its relatively low volumetric variation and high theoretical capacity. Nevertheless, the volumetric change of micro-SiOx remains a formidable challenge for existing adhesives. Here, we propose an innovative design strategy that amalgamates both rigidity and flexibility, in which rigid anion gum Arabic (GA), flexible acrylic random copolymer (ARC), and carbon nanotubes (CNTs) interwoven into a 3D network with strong interfacial adhesion and excellent mechanical properties. These attributes effectively restrict SiOx particles and favor a stable solid electrolyte interphase (SEI) layer formed on SiOx. Here, GA plays a pivotal role in dispersing CNTs and maintaining their consistent proximity to SiOx, thereby establishing stable electron conduction networks. The SiOx electrode still sustains a specific capacity of 760 mAh g−1 after 350 cycles under a high current of 1C. Additionally, at 0.2C, the SiOx electrode attains a notably high capacity of 1105 mAh g−1 with a capacity retention of 72.9 % at the 300th cycle, while exhibiting an excellent areal capacity of 1.4 mAh cm−2 even after 400 cycles. This work develops a straightforward yet highly efficacious approach for fabricating high areal capacity electrodes and offers promising prospects for improving the stableness of Si-based anodes.

Synergistic Effect of Ion Doping and Type-II Heterojunction Construction and Ciprofloxacin Degradation by MIL-68(In,Bi)-NH2@BiOBr under Visible Light.

Heterojunction structure and ion doping techniques are viable tactics in facilitating the generation and separation of photogenerated electrons and holes in photocatalysis. In the current study, a novel Bi ion-doped MIL-68(In,Bi)-NH2@BiOBr (MIBN@BOB) type-II heterojunction was first synthesized in a one-step solvothermal reaction. Doping of Bi ions not only broadened the light-sensing range but also provided reliable anchor sites for the in situ growth of BiOBr. Meanwhile, the heterostructure supplied new channels for photogenerated carriers, accelerating the transfer and inhibiting the recombination of photogenerated electron-hole. The obtained MIBN@BOB exhibited enhanced photocatalytic performance (91.1%) than MIL-68(In)-NH2 (40.8%) and BiOBr (57.5%) in ciprofloxacin (CIP) degradation under visible light, with excellent reusability. Photocatalysts were characterized in detail, and a series of photoelectrochemical tests were utilized to analyze the photoelectric properties. MIBN@BOB were deduced to conform the electron conduction mechanism of conventional type-II heterojunctions. More importantly, based on the above experiments and density functional theory (DFT) calculation, BiOBr-Bi in MIBN@BOB can serve as the major active sites of CIP enrichment, and •O2- and 1O2 generated at the BiOBr interface can react with the adsorbed CIP directly. Lastly, the possible degradation products and pathways of CIP were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). This study provides a reference for the construction of ion-doping-modified metal-organic framework (MOF)-based heterojunction photocatalysts and their application in antibiotic removal.

Hierarchically porous architecture of metal–organic framework-derived and S induced electron localization of Fe single atom sites for boosted ORR

Metal-organic frameworks (MOFs), with their high specific surface area, excellent stability and high electron transfer ability, are ideal supports for accommodating single metal atoms. However, the low utilisation of single-atom active sites limits the improvement of oxygen reduction reaction (ORR) performance.In this work, NH2-MIL-53(Al), a MOF possessing a mesoporous cage architecture, is used as the precursor to prepare N-doped carbon supports (denoted herein as N-HPC) with a well-defined mesoporous structure through pyrolysis. Thiourea was further employed for S doping and impregnated with a FePc, and heated again to yield Fe@S/N-HPC catalysts rich in accessible FeNx single atom sites. The porous structure is more accessible to Fe center atoms by exposing the active sites, provide easy electron conductivity and facilitate mass transport of ORR-intermediates. The prepared hierarchically porous architecture of NH2-MIL-53(Al)-derived and S induced electron localization of Fe SAs sites exhibit excellent ORR performance in alkaline (E1/2 = 0.88 V) medium.

Using multi-threshold non-local means joint distribution method to analysis the spatial distribution patterns of binder and fibers in gas diffusion layers of fuel cells

The gas diffusion layer (GDL) in fuel cell plays a crucial role in mass transfer, electron conduction and structural support. The distribution of binder and hydrophobic agent directly affects the mass transfer and conductivity of the fuel cell. In this study, a multi-threshold segmentation-based image processing method was used to distinguish between pores, fibers, and binder in the GDL. The relationship between binder distribution and fiber density as well as the thickness of the binder layer was investigated. Specifically, the study first utilized a joint distribution map based on grayscale values and non-local means values, with global Rényi entropy as the optimization objective. A bee algorithm was employed to search for the global optimal point, achieving threshold segmentation of micro-scale images. Subsequently, by comparing the results of element segmentation using one-dimensional and multi-dimensional segmentation methods, a three-dimensional convolutional kernel of different sizes was used to obtain the distance from each point in the structure to the edge, effectively separating adherent fibers. Finally, convolutional methods were used to analyze the relationship between the thickness of the binder layer and fiber density. It was found that there is a positive correlation between thickness and spatial density of fibers when the fiber layer is thin. These research findings provide theoretical basis for the content and distribution of binder in the basal layer process of GDL fabrication, and contribute to a more accurate description of the microstructure and properties of actual materials, enhancing the understanding of the preparation process and microstructure properties of GDL in fuel cells. The image processing method utilized in this study enables the computation of crucial parameters within the GDLs' multi-component segmentation algorithm, utilizing a limited sample size. Additionally, it offers valuable insights into the spatial distribution characteristics of fibers and the presence of thin matrix layers. These findings highlight the potential of this method for future applications in the realm of realistic three-dimensional structural reconstructions, thus holding promising prospects for further advancements in this field.

Cu2ZnSnS4/N-MWCNTs hybrid systems as counter electrode substitutes for platinum in dye-sensitized solar cells

Copper zinc tin sulfide, Cu2ZnSnS4 (CZTS) is being considered a viable option for a counter electrode due to its abundance, cost-effectiveness, catalytic activity, and other advantageous properties. However, CZTS has low electron transport capabilities, a shortcoming that can be addressed by combining it with high electron mobility carbon nanomaterials. Nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) exhibit higher electron conductivities than their pristine counterparts. This improvement is attributed to the disruption of the sp2-hybridized carbon arrangement, as some of the carbon atoms are replaced by nitrogen atoms. In this study, a counter electrode composed of a 70% CZTS and 30% N-MWCNTs mixture produced a higher electrochemical current density compared to the individual materials. This suggests that it is more electrocatalytic than CZTS and N-MWCNTs alone, ultimately leading to the highest power conversion efficiency of 6.52%.Graphical abstract

Organohydrogel-based transparent terahertz absorber via ionic conduction loss

The fast-growing terahertz technologies require high-performance terahertz absorber for suppressing electromagnetic interference. Since the dissipation mechanism in terahertz band usually focuses on electronic conduction loss, almost all terahertz absorbers are constructed with electronically conducting materials being opaque, which limits their applications in scenarios requiring high visible transmittance. Here, we demonstrate a transparent terahertz absorber based on permittivity-gradient elastomer-encapsulated-organohydrogel. Our organohydrogel-based terahertz absorber exhibits a high absorbing property (average reflection loss of 49.03 dB) in 0.5–4.5 THz band with a thin thickness of 700 μm and a high average visible transmittance of 85.51%. The terahertz absorbing mechanism mainly derives from the ionic conduction loss of the polar liquid in organohydrogel. Besides, the hydrophobic and adhesive elastomer coating endows this terahertz absorber high absorbing stability and interfacial adhesivity. This work paves a viable way to designing transparent terahertz absorbers.

The well-defined three-dimensional matrix of a micro-sized silicon/carbon composite promoting lithium-ion transportation.

Micro-sized silicon is a promising anode material due to its high theoretical capacity and low cost. However, its bulk particle size poses a challenge during electrochemical cycling, and the long ion/electron transport paths within it limit the rate capability. Herein, we propose a structural engineering approach for establishing a well-defined three-dimensional (3D) micro-sized silicon/carbon matrix to achieve efficient omnidirectional ionic and electronic conductivity within micro-sized silicon and effectively mitigate the volume changes. The prepared materials, comprising ordered two-dimensional porous silicon nanosheets, offer direct two-dimensional electrolyte transport channels aligned parallel to the layer plane and porous channels oriented perpendicular to the layer plane. These well-defined omnidirectional pathways enable more efficient electrolyte mass transport than the disordered paths within the traditional 3D porous silicon anodes. A robust carbon shell, securely bonded to silicon through dual covalent bonding, effectively shields these pathways, buffering the volume changes and offering an electronically conductive 3D carbon network.