3D Porous Skeleton Research Articles

A Fast‐Charging and Ultra‐Stable Sodium‐Ion Battery Anode Enabled by N‐Doped Bi/BiOCl in a Carbon Framework

AbstractOwing to the abundant reserves and low cost, sodium‐ion batteries (SIBs) have garnered unprecedented attention. However, their widespread adoption is hindered by the scarcity of alternative anodes with fast‐charging capability and high stability. To overcome this challenge, a fast‐charging SIB anode, N‐doped Bi/BiOCl embedded in a carbon framework (Bi/BiOCl@NC) with a fast Na+ transport channel and ultra‐high structural stability, is developed. During cycling in ether electrolyte, Bi/BiOCl@NC undergoes a remarkable transformation into a 3D porous skeleton, which significantly reduces the Na+ transport pathway and accommodates volume changes. By employing density functional theory calculations to simulate the storage behavior of Na+ in the structure, Bi/BiOCl@NC is theoretically characterized to have a low Na+ transport barrier (0.056 eV) and outstanding electronic conductivity. Such unique characteristics induce Bi/BiOCl@NC anode to have an ultra‐high Na+ storage capacity of 410 mAh·g−1 at 20 A·g−1 and exhibit outstanding cycling stability with over 2300 cycles at 10 A·g−1. This study provides a rational scenario for the fast‐charging anode design and will enlighten more advanced research to promote the exploitation of SIBs.

Constructing 3D Zincophilic Skeleton in Nitrogen-Doped Carbon Hybrid Fibers for Dendrite-Free Zn Anodes.

The Zn dendrite growth and side reactions are two major issues for the practical use of Zn metal anodes (ZMAs). Herein, an N-doped carbon-based hybrid fiber with the 3D porous skeleton and the zincophilic Cu nanoparticles (denoted as Cu@HLCF) is developed for stable ZMAs. The zincophilic Cu particles in the skeleton work as the active sites to facilitate uniform Zn nucleation. Meanwhile, the abundant pores in the framework of the hybrid fibers provide a large space to relieve the structural stress and suppress the dendrite growth. Moreover, the good mechanical characteristics of the hybrid fiber ensure its high potential applications for flexible electronics. Theoretical analysis results disclose the strong interaction between Zn and Cu sites, and experimental results demonstrate the low voltage hysteresis, high reversibility, and dendrite-free behavior of the Cu@HLCF host for Zn plating/stripping. Moreover, the solid-state Zn-ion battery (ZIB) assembled with a Cu@HLCF/Zn anode shows the prominent flexibility, impressively reliability, and outstanding cycling capability. Therefore, this work not only provides a novel design for the efficient and stable Zn metal anode but also promotes the development of flexible power sources for flexible electronics.

Nanolayered Ceramic-Confined Graphene Aerogel with Conformal Heterointerfaces for Low-Frequency Microwave Absorption.

Graphene-based aerogels have garnered considerable attention for their lightweight and efficient microwave absorption (MA) properties; however, optimizing the relationship between impedance matching and attenuation capability at low frequencies remains a challenge. In this study, a three-dimensional (3D) silicon carbonitride (SiCN) nanoceramic-coated graphene aerogel with conformal heterogeneous interfaces is constructed by precursor infiltration and pyrolysis to optimize MA performance at low frequencies. Thanks to the enhanced impedance matching and significant interfacial polarization of the two-dimensional sandwiched SiCN/graphene/SiCN cell walls and multiple scattering occurring within the 3D porous skeleton, the aerogel achieves a minimum reflection loss of -57.9 dB at an ultralow frequency of 4.92 GHz (C-band) and a broad bandwidth of 5.0 GHz at an ultralow thickness of 1.7 mm. The strategy developed here provides a method for enhancing dielectric polarization loss in graphene aerogels by the joint optimization of interfacial polarization and impedance matching, inspiring the design of high-performance graphene-based materials for low-frequency MA.

Novel core-shell structured electrocatalyst with 1D-NiTe2 over 3D metal structure for efficient hydrogen evolution reactions

Novel inexpensive materials are the focus of modern research for efficient hydrogen evolution reactions (HER) to substitute scarce and expensive platinum (Pt) based electrocatalysts. The ideal material should be durable, low-cost, efficient and possess high surface area. Earth abundant Transition metal dichalcogenides (TMDCs) are the potential group of materials for providing inexpensive source of durable HER catalysts with high surface area and active edges due to their layered structure. Here, we report a scalable single-step microwave-assisted solution phase synthesis of NiTe2 with core-shell configuration over porous three-dimensional nickel foam (3D-NF). This surface heterojunction catalyst possesses high surface area, unique needlelike morphology, and efficient performance for hydrogen evolution reactions. NiTe2 needles decorated on porous 3D-NF displayed fast HER kinetics with a reasonable overpotential of ~ −0.36 V to drive a current density of 100 mA cm−2. A small Tafel slope of ~55 mV dec−1 is observed. The catalyst showed higher stability with negligible performance degradation even after 8 h of potential cycling operation. It also demonstrated negligible current density variation at a constant applied potential for more than 15 h in 0.5 M sulfuric acid (H2SO4) solution. The 3D porous skeleton allowed high impregnation of electrolyte while the dense needlelike morphology provided high surface area and active edge sites for reactions. A thin 7 nm of amorphous oxide overlayer shell on highly crystalline NiTe2 core structure makes it a surface heterojunction catalyst (SHC) which is reported to facilitate hydrogen desorption upon charge take up and makes it an efficient electrocatalyst.

A lithiophilic hyperbranched polymer-decorated three-dimensional carbon skeleton boosting highly reversible lithium metal anode

The short cycling lifespan and serious safety issues caused by the crazy growth of dendrites, have severely restricted the practical application of Li metal anodes (LMAs) in high energy density batteries. Here, a three-dimensional (3D) porous conductive framework enriched with lithiophilic functional groups is proposed for stabilizing Li metal anodes, which is fabricated by coating hyperbranched polyol (HP) on the carbon fiber cloth (CFC) through a simple esterification reaction. The abundant lithiophilic groups distributed on HP can disperse the Li ion flow and guide the uniform nucleation of Li. The 3D porous skeleton not only promotes ion diffusion and electron transport but also provides adequate space for Li storage. Symmetrical battery configurated with CFC@HP-Li hybrid anode demonstrates stable cycling over 800 h with low voltage hysteresis at a current density of 2 mA cm−2. With a commercial LiFePO4 (LFP) cathode, the CFC@HP-Li//LFP full battery can realize a high capacity retention rate of 88.9% and a stable Coulombic efficiency (CE) close to 100% after 500 cycles at 2 C. The CFC@HP-Li anode, which is constructed by a modification of LMAs using the targeted lithiophilic coating, provides a promising strategy for the exploration of high-performance Li metal batteries (LMBs).

Organic Cross‐Linker Enabling a 3D Porous Skeleton–Supported Na3V2(PO4)3/Carbon Composite for High Power Sodium‐Ion Battery Cathode

AbstractCathodes with high energy density and good structural stability are needed for sodium‐ion batteries (SIBs) to be applied in energy storage field. Herein, a 3D porous skeleton–supported Na3V2(PO4)3/carbon composite (NVP@C‐3DPS) is synthesized via a simple sol–gel method by introducing an appropriate amount of citric acid as organic cross‐linker. The generated interlinking gel provides extensive support that orients the NVP crystal growth along the ductile carbon framework, directly exposing the active material to electrolyte. Field‐emission scanning electron microscopy results reveal that the hierarchical pores (macro and meso) are interconnected by the gel skeleton, with their thickness ranging from 50 to 300 nm. Thus, advantages are achieved, including a highly conductive continuous network, effective electrolyte contact surface areas, and short Na‐ion transfer distance. Moreover, the cross‐linking and porous property on the nanoscale gives very superior barrier‐free Na‐ion diffusion. Consequently, the NVP@C‐3DPS electrode exhibits excellent electrochemical performance, including superior high‐rate capacity (78 mA h g−1 at 192 C, approaching 76.9% of the initial capability of 98.6 mA h g−1 at 0.5 C), remarkable cycling stability (98.4% retention after 800 cycles at 1 C, 91.4% retention after 2000 cycles at 10 C), and outstanding high‐rate endurance (76.0% capacity retentions after 3000 cycles at 100 C).