3D Anode Research Articles

Fabrication of the high efficient novel SiC foam based 3D metal oxide anodes with long life to improve electrocatalytic oxidation performance

The SiC foam is a promising electrode substrate material because of its huge specific surface area and low price. The novel three dimensions (3D)-PbO2 and 3D-SnO2-Sb anodes using SiC foam as a substrate were first prepared to reduce the energy consumption of wastewater electrochemical oxidation treatment. The results of the electrochemical degradation of alizarin red S (ARS) in a flow-through reactor depicted that the ARS and chemical oxygen demand (COD) degradation rate constants of 60 pores per inch (PPI)-SiC/SnO2-Sb anode are 8 and 1.82 times that of the costly BDD electrode. For 60 PPI-SiC/SnO2-Sb/PbO2 anode, it is 10.12 and 1.35 times higher. The 3D-SiC/SnO2-Sb anode has a 142–218 times longer lifetime than that of the flat-Ti/SnO2-Sb electrode. Its lifetime is also obviously longer than that of the SnO2 electrode with the addition of an intermediate layer or advanced materials modified in the reported literature. A new failure mechanism of the 3D-SiC-based electrodes is elaborated which is different from the Ti-based electrodes. An accurate fluid model is constructed based on the micro-CT and CFD simulation to study the enhancement mechanism of the flow field. The results show that the turbulent kinetic energy and vorticity of the reactor are 3–6 times higher than that with 2D electrodes. The residence time distribution shows that the flow field of the 3D electrode exhibits a more approximate plug flow with no dead zones. Due to their high performance and long life, 3D-SiC-based SnO2-Sb and PbO2 anodes have good prospects for commercial applications.

In Situ Constructing a Film‐Coated 3D Porous Zn Anode by Iodine Etching Strategy Toward Horizontally Arranged Dendrite‐Free Zn Deposition

AbstractZn metal anode has drawn tremendous attention owing to its low cost and high volumetric capacity advantages. However, the commercial application of zinc‐based batteries is greatly deterred by Zn dendrite and severe side reactions. Interface modification is one of the most effective strategies to solve these issues. Herein, a facile iodine etching strategy to in situ construct a film‐coated 3D porous Zn anode is first proposed, which significantly reduces the nucleation overpotential of Zn while suppressing side reactions, thus resulting in uniform Zn deposition. Benefiting from the dual protection of surface coating and 3D porous Zn anode, the symmetric cell displays a long lifespan of over 5000 h at 1 mA cm–2, ≈40 times of bare Zn anode. The asymmetric cell with modified Zn anode also delivers excellent cycling stability for over 2000 cycles to achieve a high average Coulombic efficiency of 99.87%. Moreover, the capacity retention of a full battery coupled with ammonium vanadate cathode after 5000 cycles is up to 97.3%, which is much more stable than the bare Zn anode under the same condition (20%). Such a novel interfacial modification method provides a new perspective for the realization of stable metal electrodes.

A three-dimensional phenolic-based carbon anode for microbial electrochemical system with customized macroscopic pore structure to promote interior bacteria colonization

Microbial electrochemical system (MES) is an emerging wastewater treatment technology that compensates the energy demands of containments removal by in situ converting the chemical energy of organic pollutants. As the structure for exoelectrogens and the reaction site of extracellular electron transfer (EET), the anode is essential for MES. The future commercial application of MES requires efficiency and large-scale fabrication available anode. In this study, a 3D anode with millimeter-scale pores (3D-MPA) was successfully constructed by sacrificial template method, with low-cost phenolic resin as carbon precursor and polymethyl methacrylate (PMMA) pellets as template. With customized and ordered pore of 1 mm, the 3D-MPAs allowed the microorganisms to colonize inside, improving anodic space utilization efficiency. Different carbonization temperature in tested range from 700 °C to 1000 °C regulated the micrometer-scale convex structures and surface roughness of 3D-MPAs, causing electrochemical performance changes. The 3D-MPA-900 obtained the largest electroactive surface area (102 ± 4.1 cm2) and smallest ohmic resistance (1.8 ± 0.09 Ω). Equipped with MES, 3D-MPA-900 reached the highest power density and current density (2590 ± 25 mW m−2 and 5.20 ± 0.07 A m−2). Among tested 3D-MPA, the excellent performance of 3D-MPA-900 might be attributed by its convex structures with suitable size and surface coverage. The surface roughness of 3D-MPA-900 enhanced the microorganism adherence, which then promoted EET on anode surface. Generally, phenolic-based 3D-MPA made of sacrificial-template method had controllable porous structure, large-scale fabrication availability, high chemical stability and excellent mechanical property, which could be promising for the commercial application of MES.

Self-swelling derived frameworks with rigidity and flexibility enabling high-reversible silicon anodes

ABSTRACT Silicon is recognized as the most advantageous next-generation anode material for LIBs in terms of its extremely high theoretical capacity and appropriate operating voltage. However, the application of Si anode is limited by huge volume expansion emerging with cycling, which in turn induces the collapse of the electrode structure, resulting in rapid capacity decay. Here, we report a strategy using self-swelling artificial laponite to prepare a laponite/MXene/CNT composite framework with both rigidity and flexibility, which can excellently address these challenges of Si anode. The self-swelling artificial laponite participates in the construction of hierarchical and porous structures, providing sufficient buffer space to mitigate the volume expansion of the Li x Si alloying reaction. Meanwhile, tough and tightly cross-linked silicate nanosheets can improve the mechanical strength of the framework for strong structural stability. More importantly, the negative charge between the layers of artificial laponite can effectively promote fast Li-ion transport in the electrode. This free-standing silicon anode enables the preparation of high areal capacity electrodes to further enhance the energy density of LIBs and a higher reversible capacity of 2381.8 mAh/g at 0.1 C after 50 cycles with an initial coulombic of 85.6%. This work provides a simple and practical fabrication strategy for developing high-performance Si-based batteries, which can speed up their commercialization. A 3D free-standing silicon anode with both rigidity and flexibility has been constructed via self-swelling artificial laponite, which enables the preparation of high areal capacity electrodes to further enhance the energy density of LIBs.

Designing the 3D Porous Anode Based on Pore Size Dependent Li Deposition Behavior for Reversible Li Metal-Free Solid-State-Batteries

Li metal-based all-solid-state batteries (ASSBs) can potentially combine the high energy of Li metal anodes and the safety of ASSBs. Among Li metal-based ASSBs, lithium-free or anodeless ASSBs are considered optimal battery configurations because of their higher energy density and economic advantages attributed to the absence of Li metal during the battery assembly process. Despite the extensive interest in Li-free ASSBs, they continue to suffer from low Coulombic efficiency and poor cycle performance. One reason for this inferior performance is the unstable interface between the current collector and solid electrolyte (SE), which can eventually lead to inhomogeneous Li deposition, dendritic Li growth, and internal short circuits. Various approaches including 3D porous anodes have been proposed to control the Li deposition behavior and improve the reversibility of anodeless ASSBs; however, there is no clarity on the mechanism and conditions for determining the Li deposition behavior in this emerging system.In this study, we systematically investigate the Li deposition behavior depending on the pore size of 3D anode and successfully demonstrate the strategy to obtain a highly reversible 3D porous anode for Li-free ASSBs. We found that more Li deposits could be accommodated within the pores of the anode with a smaller pore size using stacked Ni particles as the Li-hosting porous anode; this implies that the Li movement into the anode occurs via diffusional Coble creep. We proposed the modification of the Ni surface with carbon coating and Ag nanoparticle decoration (Ni_C_Ag particles) to further improve the Li storage capacity of the Ni-based 3D anode and, thereby, secure the interfacial contact between the 3D Ni anode and SE. The resulting Ni_C_Ag 3D anode successfully accommodated the entire Li deposit of 2 mAh cm−2 within the porous architecture without the separation of the anode/SE interface. We clarified the improved Li storage capacity of the Ni_C_Ag anode as follows.(1) C and especially Ag electrochemically react with Li ions above 0 V; thus, Li ions can be transported to 3D Ni_C_Ag porous anode before Li deposition at the SE/anode interface at < 0 V. Further, the high Li ion diffusion coefficient of lithiated carbon and Li-Ag alloy can further reduce Li ions within the pores of the 3D anode; therefore, Li deposition can occur within the porous 3D Ni anode.(2) Lithiophilic C and Ag facilitated the movement of Li via diffusional Coble creep. In particular, Ag with solid solubility in Li (Li(Ag)) can significantly enhance Li adatom mobility because of the identical structure of Li(Ag) with pure Li.(3) Li(Ag) is widely known to lower the energy barrier for Li nucleation.With the significantly reduced nucleation overpotential and interfacial resistance, the Ni_C_Ag anode showed high reversibility in Li deposition and stripping. The Ni_C_Ag anode could be cycled for more than 60 and 100 cycles with Li3PS4 and Li6PS5Cl0.5Br0.5 SE in half cells with a capacity limit of 2 mAh cm−2 and a current density of 0.5 mA cm− 2maintaining the CE of 97.9% and 96.9 %, respectively. Further, the synergistic effects of the stable anode/SE interface and reduced nucleation energy barrier enable stable NCM full-cell cycling at a room temperature of 30 °C. The NCM811 cathode/Ni_C_Ag anode full cell in the Li-free configuration showed an initial areal discharge capacity of 2 mAh cm−2, and it operated stably with a CE of 99.47% for 100 cycles. Figure 1

In situ generation of Li3N concentration gradient in 3D carbon-based lithium anodes towards highly-stable lithium metal batteries

The uncontrolled dendrite growth of lithium metal anodes (LMAs) caused by unstable anode/electrolyte interface and uneven lithium deposition have impeded the practical applications of lithium metal batteries (LMBs). Constructing a robust artificial solid electrolyte interphase (SEI) and regulating the lithium deposition behavior is an effective strategy to address these issues. Herein, a three-dimensional (3D) lithium anode with gradient Li3N has been in-situ fabricated on carbon-based framework by thermal diffusion method (denoted as CC/Li/Li3N). Density functional theory (DFT) calculations reveal that Li3N can effectively promote the transport of Li+ due to the low energy barrier of Li+ diffusion. As expected, the Li3N-rich conformal artificial SEI film can not only effectively stabilize the interface and avoid parasitic reactions, but also facilitate fast Li+ transport across the SEI layer. The anode matrix with uniformly distributed Li3N can enable homogenous deposition of Li, thus preventing Li dendrite propagation. Benefiting from these merits, the CC/Li/Li3N anode achieves ultralong-term cycling for >1000 h at a current density of 2 mA cm−2 and dendrite-free Li deposition at an ultrahigh rate of 20 mA cm−2. Moreover, the full cells coupled with LiFePO4 cathodes show extraordinary cycling stability for >300 cycles in liquid-electrolyte-based batteries and display a high-capacity retention of 96.7% after 100 cycles in solid-state cells, demonstrating the promising prospects for the practical applications of LMBs.

Phosphorus-functionalized low-crystallinity transition-metal oxide nanorod arrays grown on carbon cloth for high-performance asymmetric supercapacitors

Transition-metal oxides as the pseudocapacitive material have been increasingly investigated due to their high theoretical specific capacitance for supercapacitors (SCs). However, restricted to lack of active sites and poor conductivity, they usually display limited experimental capacitance, barely satisfying high energy density of SCs. Herein, we describe phosphorus functionalized low-crystallinity Co3O4 and Fe2O3 nanorod arrays on carbon cloth (Co3O4-P and Fe2O3-P), which can respectively behave as the flexible 3D cathode and anode for SCs. The formed phosphide on the surface of metal oxide provides the enhancement of electron transfer and the reduction of ions diffusion pathway. The optimized Co3O4-P 1.0 h cathode and Fe2O3-P 1.0 h anode deliver a high capacitance of 1180 and 477 mF cm−2, respectively. The asymmetric supercapacitor Co3O4-P//Fe2O3-P has been verified with an operating voltage of 1.5 V and stability over 5000 cycles and delivers an energy density of 73.6 μWh cm−2 at a power density of 0.38 mW cm−2. The phosphorus activation is expected to be widely applicable for the fabrication of porous and low-crystalline transition-metal oxide, thus opening up new avenues for energy storage.

Suppressing the Exacerbated Hydrogen Evolution of Porous Zn Anode with an Artificial Solid-Electrolyte Interphase Layer.

Rechargeable Zn batteries are widely studied as aqueous, safe, and environmentally friendly alternatives to Li-ion batteries. The 3D porous Zn anode has been extensively reported for suppressing Zn dendrite growth and accelerating the electrode kinetics. However, we demonstrate herein that the undesirable hydrogen evolution reaction (HER) is also exacerbated for porous Zn electrode. Therefore, a polytetrafluoroethylene (PTFE) coating is further applied on the porous Zn serving as the artificial solid-electrolyte interphase (SEI), which is demonstrated to effectively inhibit the hydrogen evolution and maintain the Zn plating kinetics. By utilizing the synergistic effects of the porous morphology and artificial SEI layer, better performances are obtained over porous Zn or bare Zn foil, including dendrite-free Zn plating/stripping up to 2000 h at 2 mA cm-2 and extended cycling in the Zn||V2O5 cell. This work suggests two complementary strategies for achieving simultaneously dendrite-free and side-reaction-suppressed Zn batteries.

3D hierarchical porous carbon foams as high‐performance free‐standing anodes for microbial fuel cells

AbstractMicrobial fuel cells (MFCs) that can directly convert chemical energy of organic matter into electrical energy are expected to continuously obtain energy from wastewater. However, the practical application of MFCs is still limited by unsatisfactorily low power output due to low bacterial loading capacity and relatively poor extracellular electron transport (EET) efficiency between anode and electrochemically active biofilm. Herein, hierarchical porous carbon foams (HPCFs) prepared by pyrolyzing nanoscale Fe‐MIL‐88B‐NH2 modified seitan composite were developed as 3D free‐standing MFC anodes. Its marcoporous structure and good biocompatibility favor the bacterial adhesion, while the N‐doped carbon skeleton, abundant mesopores and iron ions boost the bacteria‐electrode charge transfer efficiency. As a result, the HPCF anodes equipped MFCs deliver a maximum power density of 11.21 W m−3 and a current density of 23.11 A m−3, outperforming the most previously reported 3D porous anodes. This study provides a new idea for the design of anodes for high‐performance MFCs.image

Sustainable silicon micro-dendritic anodes integrated by a moderately cross-linked polymer binder with superior elasticity and adhesion

The extensive application of silicon (Si) anodes is still impeded, although Si has long been considered as the most potential anode material for the high-energy lithium-ion batteries. In the composition of anodes, binders with a small proportion contribute no direct capacity to the cell, but play a vital role in addressing the issues associated with Si materials (e.g., huge volume expansion, unstable solid electrolyte interphase (SEI) layer and low electrical conductivity). Herein, we design a moderately cross-linked polymer binder polyacrylic acid (PAA)–sodium alginate (SA) to balance the degree of crosslinking and the number of free groups within this polymer structure via a simple esterification reaction, which can support micro-sized silicon dendrites (SD) to form a three-dimensional (3D) anode. The PAA-SA binder with a moderately cross-linked structure can simultaneously realize the mechanical strength, chemical stability, and polymer viscosity, resulting the Si anodes with restricted volume expansion and stable SEI layers during long cycles. Therefore, the SD/PAA-SA anode exhibited superior cycling performance (2929.8 mA h g−1 for 1st cycle, initial Coulombic efficiency of 80.1 % and 1419.8 mA h g−1 at 1 A g−1 after 200th cycle) and good mechanical properties. This work designs a water-soluble binder with a moderately cross-linked polymer structure, which can be applied to developing electrodes with compatible sustainability and electrochemical activity.

Dual Vertically Aligned Electrode-Inspired High-Capacity Lithium Batteries.

Lithium (Li) dendrite formation and poor Li+ transport kinetics under high‐charging current densities and capacities inhibit the capabilities of Li metal batteries (LMBs). This study proposes a 3D conductive multichannel carbon framework (MCF) with homogeneously distributed vertical graphene nanowalls (VGWs@MCF) as a multifunctional host to efficiently regulate Li deposition and accelerate Li+ transport. A novel electrode for both Li|VGWs@MCF anode and LFP|VGWs@MCF (NCM811|VGWs@MCF) cathode is designed and fabricated using a dual vertically aligned architecture. This unique hierarchical structure provides ultrafast, continuous, and smooth electron transport channels; furthermore, it furnishes outstanding mechanical strength to support massive Li deposition at ultrahigh rates. As a result, the Li|VGWs@MCF anode exhibits outstanding cycling stability at ultrahigh currents and capacities (1000 h at 10 mA cm–2 and 10 mAh cm–2, and 1000 h at 30 mA cm–2 and 60 mAh cm–2). Moreover, full cells made of such 3D anodes and freestanding LFP|VGWs@MCF (NCM811|VGWs@MCF) cathodes with conspicuous mass loading (45 mg cm–2 for LFP and 35 mg cm–2 for NCM811) demonstrate excellent areal capacities (6.98 mAh cm–2 for LFP and 5.6 mAh cm–2 for NCM811). This strategy proposes a promising direction for the development of high‐energy‐density practical Li batteries that combine safety, performance, and sustainability.

Metallic three-dimensional porous siligraphene as a superior anode material for Li/Na/K-ion batteries

Due to the high specific capacity and low open circuit voltage (OCV), 2D siligraphene has been widely considered as a promising anode material for metal ion batteries (MIBs). Nonetheless, its electrochemical performance is greatly impeded by low mechanical stiffness, poor hopping dynamics and small pore size. Motivated by the great success of 3D carbon materials, we propose a metallic porous 3D-SiC anode using the corresponding 2D tetragonal SiC as a structural unit. By first principles molecular dynamics, mechanical property and phonon spectrum calculations, it is found that 3D-SiC possesses good thermal, mechanical and dynamical stability. The maximum Young’s and bulk moduli of 3D-SiC are 217.16, 400.90 GPa, respectively, exhibiting a moderate mechanical stiffness. More importantly, the intrinsically high electrical conductivity, unique porous structure and low mass density make the 3D-SiC a promising anode candidate for Li/Na/K-ion batteries with small volume changes (6.43 %, 3.75 % and 8.66 %), low diffusion barriers (0.17, 0.19 and 0.017 eV), high storage capacities (947, 947 and 724 mA h/g) and low average OCVs (0.56, 0.34 and 0.11 V). The encouraging results show that siligraphene-based porous 3D anodes are worthy of further investigation for MIBs.

Recent progress on three-dimensional nanoarchitecture anode materials for lithium/sodium storage

High-performance batteries with high density and low cost are needed for the development of large-scale energy storage fields such as electric vehicles and renewable energy systems. The anode with three-dimensional (3D) nanoarchitecture is one of the most attractive candidates for high-performance lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its efficient electron/ion transport and high active material mass loading. Although some important breakthroughs have been made in 3D nanoarchitecture anode materials, more improvements are still needed for high cycling stability and high energy density. Herein, the latest research progress of 3D nanoarchitecture anode materials for LIBs and SIBs is reviewed, including nanoporous metal, nanoporous graphene, and their derived foams. Specifically, the storage properties of Li/Na ions, the kinetics of ion/electron transport, and specific chemical interactions are discussed based on the structure design. In addition, the research strategies and structural characteristics of 3D nanoarchitecture anode materials are summarized, providing a reference for the further development of LIBs and SIBs. Meanwhile, the future research directions of LIBs and SIBs have also prospected.

Ultrahigh Lithium Storage Capacity of Al2C Monolayer in a Restricted Multilayered Growth Mechanism.

Designing anode materials with high lithium specific capacity is crucial to the development of high energy density lithium (ion) batteries. Herein, a distinctive lithium growth mechanism, namely, the restricted multilayered growth for lithium, and a strategy for lithium storage are proposed to achieve a balance between ultrahigh specific capacity and the need to avert uncontrolled dendritic growth of lithium. In particular, based on first-principles computation, we show that the Al2C monolayer with a planar tetracoordinate carbon structure can be an ideal platform for realizing the restricted multilayered growth mechanism as a two-dimensional (2D) anode material. Furthermore, the Al2C monolayer exhibits the ultrahigh specific capacity of lithium of 4059 mAh/g, yet with a low diffusion barrier of 0.039-0.17 eV and low open circuit voltage in the range of 0.002-0.34 V. These novel properties render the Al2C monolayer a promising anode material for future lithium (ion) batteries. Our study also offers a design of promising 2D anode materials with a high specific capacity, fast lithium-ion diffusion, and safe lithium storage.

High-performance LiFePO4 and SiO@C/graphite interdigitated full lithium-ion battery fabricated via low temperature direct write 3D printing

Lithium-ion batteries (LIBs) composed of thin tape–casted electrodes face some intrinsic challenges especially the trade-off between energy density and power density. Three-dimensional (3D) structural batteries fabricated by 3D printing have the potential to overcome this challenge. Silicon oxide–based materials are promising candidates for the next-generation high-performance LIBs. In this study, interdigitated full batteries composed of comb-like LiFePO4 3D cathodes and comb-like SiO@C/graphite 3D anodes are fabricated via low temperature direct writing 3D printing process. The 3D printing at a low temperature of below −20 °C enables the 3D-printed SiO@C/graphite electrodes obtain a high porosity of ∼60% and tri-modally hierarchical porous microstructure. Comb-like 3D SiO@C/graphite anodes with the thickness of ∼418 μm, ∼692 μm, and ∼806 μm and corresponding mass loading of ∼39.2 mg cm-2, ∼60.9 mg cm-2, ∼84.3 mg cm-2, respectively, are fabricated to evaluate their electrochemical performance. These thick 3D electrodes display impressive areal capacities of ∼17.9, ∼26.7, and ∼33.2 mA h cm-2 @ 0.3 C depending on their electrode thickness. Coupled with comb-like LiFePO4 3D cathodes, interdigitated full batteries with two N/P ratios of 0.91 and 0.82 are fabricated. These full batteries exhibit high energy density, high power density, and stable cycling performance.

Reversible Oxygen-Rich Functional Groups Grafted 3D Honeycomb-Like Carbon Anode for Super-Long Potassium Ion Batteries

Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K+, but the basic storage mechanism is still unclear. Herein, we construct and optimize 3D honeycomb-like carbon grafted with plentiful COOH/C = O functional groups (OFGC) as anodes for potassium ion batteries. The OFGC electrode with steady structure and rich functional groups can effectively contribute to the capacity enhancement and the formation of stable solid electrolyte interphase (SEI) film, achieving a high reversible capacity of 230 mAh g−1 at 3000 mA g−1 after 10,000 cycles (almost no capacity decay) and an ultra-long cycle time over 18 months at 100 mA g−1. The study results revealed the reversible storage mechanism between K+ and COOH/C = O functional groups by forming C-O-K compounds. Meanwhile, the in situ electrochemical impedance spectroscopy proved the highly reversible and rapid de/intercalation kinetics of K+ in the OFGC electrode, and the growth process of SEI films. In particular, the full cells assembled by Prussian blue cathode exhibit a high energy density of 113 Wh kg−1 after 800 cycles (calculated by the total mass of anode and cathode), and get the light-emitting diodes lamp and ear thermometer running.

A Review on 3D Zinc Anodes for Zinc Ion Batteries.

Zinc ion batteries (ZIBs) have been gradually developed in recent years due to their abundant resources, low cost, and environmental friendliness. Therefore, ZIBs have received a great deal of attention from researchers, which are considered as the next generation of portable energy storage systems. However, poor overall performance of ZIBs restricts their development, which is attributed to zinc dendrites and a series of side reactions. Constructing 3D zinc anodes has proven to be an effective way to significantly improve their electrochemical performance. In this review, the challenges of zinc anodes in ZIBs, including zinc dendrites, hydrogen evolution and corrosion, as well as passivation, are comprehensively summarized and the energy storage mechanisms of the zinc anodes and 3D zinc anodes are discussed. 3D zinc anodes with different structures including fiberous, porous, ridge-like structures, plated zinc anodes on different substrates and other 3D zinc anodes, are subsequently discussed in detail. Finally, emerging opportunities and perspectives on the material design of 3D zinc anodes are highlighted and challenges that need to be solved in future practical applications are discussed, hopefully illuminating the way forward for the development of ZIBs.

Three-dimensional ordered macroporous patterned structure for dendrite-free and stable zinc anodes

The irregular formation of zinc dendrites and side reactions on Zn anodes severely restrict the stability and cycling life of aqueous Zn-ion batteries. Herein, we report a dendrite-free zinc anode with three-dimensional ordered macroporous patterned structure (3D Zn). The 3D Zn anode can provide enlarged electrochemically active surface areas towards uniform electric field distribution with reduced local current densities and a regulated ion distribution for oriented zinc plating/stripping. The 3D structure with homogeneous Zn can also facilitate charge transfer and lower polarizations, to boost the electrochemical reaction kinetics. Consequently, a lowered nucleation overpotential of 19.2 mV and an extended lifespan of 1000 h are achieved in the 3D Zn-based symmetric cells. Moreover, 3D Zn//MnO2 full cells retain 80.9% of the initial capacity at 1 A/g after 1500 cycles with outstanding reversibility. Our work presents a feasible approach to develop dendrite-free and stable metal anodes for safe energy storage systems.

Sodium alginate reinforced 3D lithiophilic Ag–Cu framework for ultrastable Li deposition

The implementation of lithium (Li) anode has been greatly hindered by the low columbic efficiency (CE) and safety concerns, and these are also the main issues in anode-free batteries. Using three-dimensional (3D) anode, such as copper foam (CF), can lower the areal current density and reduce the overpotential, but the larger interface will induce more SEI issues, and additionally, its lithiophobic and naturally curving surface leads to difficult Li nucleation and even more uneven Li deposition. In this paper, sandwich-structured SA@Ag@CF electrode is fabricated in which CF substrate is uniformly covered by nano-sized Ag particle and an extra sodium alginate (SA) layer is further loaded on it. Synergistic effect has been brought by thus-designed electrode, in which Ag much increases the Li-affinity, on the other hand, the tightly-absorbed SA reduces electrolyte contact, alleviates the volume variation and regulates the Li+ diffusion. Ultra-stable Li deposition on 3D substrate has been first realized by the SA@Ag@CF electrode in corrosive carbonate electrolyte. With the SA@Ag@CF anode, the full cells demonstrate much improved long-term stability and rate performance.

Synergistic effect of modest pores and lithiophilic surface on 3D current collectors for stable Li metal anodes

The increasing demand for high energy density battery systems has accelerated the development of lithium metal batteries, and it is imperative to seek strategies for alleviating the large volume change and inhibiting dendrite growth of the Li metal anode. 3D porous anode current collectors cooperated with surface modification have been considered as effective methods. Herein, we develop 3D porous Cu with modest pores by powder metallurgy method, combined with surface modification by lithiophilic Ag nanoparticles. The obtained ingenious porous structure ensures the reduction of local current density when served as the Li anode current collector, while the Ag nanoparticle layer provides numerous lithiophilic nucleation sites. Smooth and uniform Li plating morphologies are confirmed on the PM Cu@AgNP electrode surface, and the PM Cu@AgNP-Li symmetric cell presents a stable cycle of 1600 h, which effectively inhibits the Li dendrite growth. When coupled with the LiFePO 4 cathode, the assembled full cell exhibits superb capacity retention and stability for 600 cycles at 0.5 C. This facile and rational strategy with synergistic effect of modest pores and surface lithiophilicity provides a way to achieve highly stable Li metal anodes for next-generation Li batteries. • Powder metallurgy method is introduced to prepare the Li metal anode current collector. • Synergistic effect of the structure and lithiophilicity makes stable Li anode. • An average pore size of 21.2 µm is modest for the porous current collector. • Surface Ag nanoparticles significantly reduce Li nucleation overpotential.