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1.
High‐capacity electrode materials play a vital role for high‐energy‐density lithium‐ion batteries. Silicon (Si) has been regarded as a promising anode material because of its outstanding theoretical capacity, but it suffers from an inherent volume expansion problem. Binders have demonstrated improvements in the electrochemical performance of Si anodes. Achieving ultrahigh‐areal‐capacity Si anodes with rational binder strategies remains a significant challenge. Herein, a binder‐lithiated strategy is proposed for ultrahigh‐areal‐capacity Si anodes. A hard/soft modulated trifunctional network binder (N‐P‐LiPN) is constructed by the partially lithiated hard polyacrylic acid as a framework and partially lithiated soft Nafion as a buffer via the hydrogen binding effect. N‐P‐LiPN has strong adhesion and mechanical properties to accommodate huge volume change of the Si anode. In addition, lithium‐ions are transferred via the lithiated groups of N‐P‐LiPN, which significantly enhances the ionic conductivity of the Si anode. Hence, the Si@N‐P‐LiPN electrodes achieve the highest initial Coulombic efficiency of 93.18% and a stable cycling performance for 500 cycles at 0.2 C. Specially, Si@N‐P‐LiPN electrodes demonstrate an ultrahigh‐areal‐capacity of 49.59 mAh cm?2. This work offers a new approach for inspiring the battery community to explore novel binders for next‐generation high‐energy‐density storage devices.  相似文献   

2.
Li metal anodes are going through a great revival but they still encounter grand challenges. One often neglected issue is that most reported Li metal anodes are only cyclable under relatively low current density (<5 mA cm?2) and small areal capacity (<5 mAh cm?2), which essentially limits their high‐power applications and results in ineffective Li utilization (<1%). Herein, it is reported that surface alloyed Li metal anodes can enable reversible cycling with ultrafast rate and ultralarge areal capacity. Low‐cost Si wafers are used and are chemically etched down to 20–30 µm membranes. Simply laminating a Si membrane onto Li foil results in the formation of LixSi alloy film fused onto Li metal with mechanical robustness and high Li‐ion conductivity. Symmetric cell measurements show that the surface alloyed Li anode has excellent cycling stability, even under high current density up to 25 mA cm?2 and unprecedented areal capacity up to 100 mAh cm?2. Furthermore, the surface alloyed Li anode is paired with amorphous MoS3 cathode and achieves remarkable full‐cell performance.  相似文献   

3.
Conventional graphite anodes can hardly intercalate sodium (Na) ions, which poses a serious challenge for developing Na‐ion batteries. This study details a novel method that involves single‐step laser‐based transformation of urea‐containing polyimide into an expanded 3D graphene anode, with simultaneous doping of high concentrations of nitrogen (≈13 at%). The versatile nature of this laser‐scribing approach enables direct bonding of the 3D graphene anode to the current collectors without the need for binders or conductive additives, which presents a clear advantage over chemical or hydrothermal methods. It is shown that these conductive and expanded 3D graphene structures perform exceptionally well as anodes for Na‐ion batteries. Specifically, an initial coulombic efficiency (CE) up to 74% is achieved, which exceeds that of most reported carbonaceous anodes, such as hard carbon and soft carbon. In addition, Na‐ion capacity up to 425 mAh g?1 at 0.1 A g?1 has been achieved with excellent rate capabilities. Further, a capacity of 148 mAh g?1 at a current density of 10 A g?1 is obtained with excellent cycling stability, opening a new direction for the fabrication of 3D graphene anodes directly on current collectors for metal ion battery anodes as well as other potential applications.  相似文献   

4.
While existing carbonaceous anodes for lithium–ion batteries (LIBs) are approaching a practical capacitive limit, Si has been extensively examined as a potential alternative because it shows exceptional gravimetric capacity (3579 mA h g?1) and abundance. However, the actual implementation of Si anodes is impeded by difficulties in electrode calendering processes and requirements for excessive binding and conductive agents, arising from the brittleness, large volume expansion (>300%), and low electrical conductivity (1.56 × 10?3 S m?1) of Si. In one rational approach to using Si in high‐energy LIBs, mixing Si‐based materials with graphite has attracted attention as a feasible alternative for next‐generation anodes. In this study, graphite‐blended electrodes with Si nanolayer‐embedded graphite/carbon (G/SGC) are demonstrated and detailed one‐to‐one comparisons of these electrodes with industrially developed benchmarking samples are performed under the industrial electrode density (>1.6 g cc?1), areal capacity (>3 mA h cm?2), and a small amount of binder (3 wt%) in a slurry. Because of the favorable compatibility between SGC and conventional graphite, and the well‐established structural features of SGC, great potential is envisioned. Since this feasible study utilizes realistic test methods and criteria, the rigorous benchmarking comparison presents a comprehensive understanding for developing and characterizing Si‐based anodes for practicable high‐energy LIBs.  相似文献   

5.
A self‐healing polymer (SHP) with abundant hydrogen bonds, appropriate viscoelasticity, and stretchability is a promising binder to improve cycle performance of Si microparticle anodes in lithium (Li) ion batteries. Besides high capacity and long cycle life, efficient rate performance is strongly desirable for practical Si anode implementation. Here, polyethylene glycol (PEG) groups are incorporated into the SHP, facilitating Li ionic conduction within the binder. The concept of the SHP‐PEG binder involves improving the interface between Si microparticles and electrolytes after cycling based on the combination of self‐healing ability and fast Li ionic conduction. Through the systematic study of mixing PEG Mw and ratio, the polymeric binder combining SHP and PEG with Mw 750 in an optimal ratio of 60:40 (mol%) achieves a high discharging capacity of ≈2600 mA h g?1, reasonable rate performance especially when >1C and maintains 80% of their initial capacity even after ≈150 cycles at 0.5C. The described concept for the polymeric binder, embedding both self‐healing ability and high Li ionic conductivity, should be equally useful for next generation batteries utilizing high capacity materials which suffer from huge volume change during cycling.  相似文献   

6.
All‐solid‐state batteries (ASSBs) with silicon anodes are promising candidates to overcome energy limitations of conventional lithium‐ion batteries. However, silicon undergoes severe volume changes during cycling leading to rapid degradation. In this study, a columnar silicon anode (col‐Si) fabricated by a scalable physical vapor deposition process (PVD) is integrated in all‐solid‐state batteries based on argyrodite‐type electrolyte (Li6PS5Cl, 3 mS cm?1) and Ni‐rich layered oxide cathodes (LiNi0.9Co0.05Mn0.05O2, NCM) with a high specific capacity (210 mAh g?1). The column structure exhibits a 1D breathing mechanism similar to lithium, which preserves the interface toward the electrolyte. Stable cycling is demonstrated for more than 100 cycles with a high coulombic efficiency (CE) of 99.7–99.9% in full cells with industrially relevant areal loadings of 3.5 mAh cm?2, which is the highest value reported so far for ASSB full cells with silicon anodes. Impedance spectroscopy revealed that anode resistance is drastically reduced after first lithiation, which allows high charging currents of 0.9 mA cm?2 at room temperature without the occurrence of dendrites and short circuits. Finally, in‐operando monitoring of pouch cells gave valuable insights into the breathing behavior of the solid‐state cell.  相似文献   

7.
Metal phosphides are promising anode candidates for sodium‐ion batteries (SIBs) due to their high specific capacity and low operating potential but suffer from poor cycling stability caused by huge volume expansion and poor solid‐state ion transfer rate. Herein, a new strategy to grow a new class of mesoporous metal phosphide nanoarrays on carbon felt (CF) as binder‐free anodes for SIBs is reported. The resultant integrated electrodes demonstrate excellent cycling life up to 1000 times (>90% retention rate) and high rate capability of 535 mAh g?1 at a current density of 4 A g?1. Detailed characterization reveals that the synergistic effect of unique mesoporous structure for accommodating huge volume expansion during sodiation/desodiation process, ultrasmall primary particle size (≈10 nm) for providing larger electrode/electrolyte contact area and shorter ion diffusion distance, and 3D conductive networks for facilitating the electrochemical reaction, leads to the extraordinary battery performance. Remarkably, a full SIB using the new CoP4/CF anode and a Na3V2(PO4)2F3 cathode delivers an average operating voltage of ≈3.0 V, a reversible capacity of 553 mAh g?1, and very high energy density of ≈280 Wh kg?1 for SIBs. A flexible SIB with outstanding mechanical strength based on this binder‐free new anode is also demonstrated.  相似文献   

8.
Achieving a high areal capacity is essential for the transfer of outstanding laboratory electrode results to commercial applications and also to ensure there exists a capacity matched cathode and anode for a properly tuned battery. Despite intensive efforts, most electrode materials exhibit areal capacities lower than that of the graphite anodes (4 mA h cm?2). An effective and low‐cost approach is reported to attain a high areal capacity via an intense densification by compacting a porous carbon nanotube sponge grafted with Co3O4 nanoparticles. The hybrid sponge can be compacted to a large degree (up to a tenfold densification) while still keeping its structural integrity and the 3D porous network. This method allows achieving a mass loading of up ?to 14.3 mg cm?2 and an areal capacity of 12 mA h cm?2 (at a current density of 200 mA g?1) together with a gravimetric capacity of >800 mA h g?1. This densification by compaction approach offers an effective and low‐cost strategy to develop high mass loading and areal capacity electrodes for practical energy storage systems.  相似文献   

9.
Described here is the production and characterization of a scalable method to produce 3D structured lithium ion battery anodes using free‐standing papers of porous silicon nanowires (Si‐NW) and graphene nanoribbons (GNRs). Using simple filtration methods, GNRs and Si‐NWs can be entangled into a mat thereby forming Si‐NW GNR papers. This produces anodes with high gravimetric capacity (up to 2500 mA h g?1) and high areal and volumetric capacities (up to 11 mA h cm?2 and 3960 mA h cm?3). The compact structure of the anode is possible since the GNR volume occupies a high proportion of empty space within the composite paper. These Si‐NW/GNR papers have been cycled for over 300 cycles, exhibiting a stable life cycle. Combined with LiCoO2 nanowires, a full battery is produced with high energy density (386 Wh kg?1), meeting requirements for high performance devices.  相似文献   

10.
Silicon is attracting enormous attention due to its theoretical capacity of 4200 mAh g?1 as an anode for Li‐ion batteries (LIBs). It is of fundamental importance and challenge to develop low‐temperature reaction route to controllably synthesize Si/Ti3C2 MXene LIBs anodes. Herein, a novel and efficient strategy integrating in situ orthosilicate hydrolysis and a low‐temperature reduction process to synthesize Si/Ti3C2 MXene composites is reported. The hydrolysis of tetraethyl orthosilicate leads to homogenous nucleation and growth of SiO2 nanoparticles on the surface of Ti3C2 MXene. Subsequently, SiO2 nanoparticles are reduced to Si via a low‐temperature (200 °C) reduction route. Importantly, Ti3C2 MXene not only provides fast transfer channels for Li+ and electrons, but also relieves volume expansion of Si during cycling. Moreover, the characteristics of excellent pseudocapacitive performance and high conductivity of Ti3C2 MXene can synergistically contribute to the enhancement of energy storage performance. As expected, Ti3C2/Si anode exhibits an outstanding specific capacity of 1849 mAh g?1 at 100 mA g?1, even retaining 956 mAh g?1 at 1 A g?1. The low‐temperature synthetic route to Si/Ti3C2 MXene electrodes and involved battery‐capacitive dual‐model energy storage mechanism has potential in the design of novel high‐performance electrodes for energy storage devices.  相似文献   

11.
Owing to its high theoretical specific capacity (1166 mA h g?1) and particularly its advantage to be paired with a lithium‐metal‐free anode, lithium sulfide (Li2S) is regarded as a much safer cathode for next‐generation advanced lithium–sulfur (Li–S) batteries. However, the low conductivity of Li2S and particularly the severe “polysulfide shuttle” of lithium polysulfide (LiPS) dramatically hinder their practical application in Li–S batteries. To address such issues, herein a bifuctional 3D metal sulfide‐decorated carbon sponge (3DTSC), which is constructed by 1D carbon nanowires cross‐linked with 2D graphene nanosheets with high conductivity and polar 0D metal sulfide nanodots with efficient electrocatalytic activity and strong chemical adsorption capability for LiPSs, is presented. Benefiting from the well‐designed multiscale, multidimensional 3D porous nanoarchitecture with high conductivity, and efficient electrocatalytic and absorption ability, the 3DTSC significantly mitigates LiPS shuttle, improves the utilization of Li2S, and facilitates the transport of electrons and ions. As a result, even with a high Li2S loading of 8 mg cm?2, the freestanding 3DTSC‐Li2S cathode without a polymer binder and metallic current collector delivers outstanding electrochemical performance with a high areal capacity of 8.44 mA h cm?2.  相似文献   

12.
Lithium metal is the most promising anode material for high‐energy‐density batteries due to its high specific capacity of 3860 mAh g?1 and low reduction potential of ?3.04 V versus standard hydrogen electrode. However, huge volume change, safety concerns, and low efficiency impede the practical applications of Li metal anodes. Herein, it is shown that the nitrogen‐doped graphene modified 3D porous Cu (3DCu@NG) current collector can mitigate the above problems. The N‐doped graphene, coating on the surface of 3D current collector, not only contributes to a uniform Li+ flux, but also leads to a scattered distribution of electrons throughout the surface, finally contributing to a uniform Li deposition and the improved electrochemical performance. In addition, the continuously porous structure of 3DCu@NG provides a space for the metallic Li deposition and could effectually accommodate the volume expansion during cycling. As a result, the Li‐3DCu@NG anode exhibits a high areal capacity of 4 mAh cm?2, a high Li utilization of ≈98%, and an ultralow voltage hysteresis of ≈19 mV. The multifunctional N‐doped graphene modified 3D porous current collector promisingly provides a strategy for safe and high‐energy lithium metal anodes.  相似文献   

13.
The application of lithium (Li) metal anodes in Li metal batteries has been hindered by growth of Li dendrites, which lead to short cycling life. Here a Li‐ion‐affinity leaky film as a protection layer is reported to promote a dendrite‐free Li metal anode. The leaky film induces electrokinetic phenomena to enhance Li‐ion transport, leading to a reduced Li‐ion concentration polarization and homogeneous Li‐ion distribution. As a result, the dendrite‐free Li metal anode during Li plating/stripping is demonstrated even at an extremely high deposition capacity (6 mAh cm?2) and current density (40 mA cm?2) with improved Coulombic efficiencies. A full cell battery with the leaky‐film protected Li metal as the anode and high‐areal‐capacity LiNi0.8Co0.1Mn0.1O2 (NCM‐811) (≈4.2 mAh cm?2) or LiFePO4 (≈3.8 mAh cm?2) as the cathode shows improved cycling stability and capacity retention, even at lean electrolyte conditions.  相似文献   

14.
Alloy materials such as Si and Ge are attractive as high‐capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge–charge processes. Compared to the over‐emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid‐electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy‐based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF‐dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb‐coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g?1 after 200 cycles at 500 mA g?1, compared to only 72% and 170 mAh g?1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long‐term cycling stability for alloy‐based anode materials.  相似文献   

15.
To develop a long cycle life and good rate capability electrode, 3D hierarchical porous α‐Fe2O3 nanosheets are fabricated on copper foil and directly used as binder‐free anode for lithium‐ion batteries. This electrode exhibits a high reversible capacity and excellent rate capability. A reversible capacity up to 877.7 mAh g?1 is maintained at 2 C (2.01 A g?1) after 1000 cycles, and even when the current is increased to 20 C (20.1 A g?1), a capacity of 433 mA h g?1 is retained. The unique porous 3D hierarchical nanostructure improves electronic–ionic transport, mitigates the internal mechanical stress induced by the volume variations of the electrode upon cycling, and forms a 3D conductive network during cycling. No addition of any electrochemically inactive conductive agents or polymer binders is required. Therefore, binder‐free electrodes further avoid the uneven distribution of conductive carbon on the current collector due to physical mixing and the addition of an insulator (binder), which has benefits leading to outstanding electrochemical performance.  相似文献   

16.
This study proposes a conformal surface coating of conducting polymer for protecting 1D nanostructured electrode material, thereby enabling a free‐standing electrode without binder for sodium ion batteries. Here, polypyrrole (PPy), which is one of the representative conducting polymers, encapsulated cobalt phosphide (CoP) nanowires (NWs) grown on carbon paper (CP), finally realizes 1D core–shell CoP@PPy NWs/CP. The CoP core is connected to the PPy shell via strong chemical bonding, which can maintain a Co–PPy framework during charge/discharge. It also possesses bifunctional features that enhances the charge transfer and buffers the volume expansion. Consequently, 1D core–shell CoP@PPy NWs/CP demonstrates superb electrochemical performance, delivering a high areal capacity of 0.521 mA h cm?2 at 0.15 mA cm?2 after 100 cycles, and 0.443 mA h cm?2 at 1.5 mA cm?2 even after 1000 cycles. Even at a high current density of 3 mA cm?2, a significant areal discharge capacity reaching 0.285 mA h cm?2 is still maintained. The outstanding performance of the CoP@PPy NWs/CP free‐standing anode provides not only a novel insight into the modulated volume expansion of anode materials but also one of the most effective strategies for binder‐free and free‐standing electrodes with decent mechanical endurance for future secondary batteries.  相似文献   

17.
Secondary batteries based on earth‐abundant potassium metal anodes are attractive for stationary energy storage. However, suppressing the formation of potassium metal dendrites during cycling is pivotal in the development of future potassium metal‐based battery technology. Herein, a promising artificial solid‐electrolyte interphase (ASEI) design, simply covering a carbon nanotube (CNT) film on the surface of a potassium metal anode, is demonstrated. The results show that the spontaneously potassiated CNT framework with a stable self‐formed solid‐electrolyte interphase layer integrates a quasi‐hosting feature with fast interfacial ion transport, which enables dendrite‐free deposition of potassium at an ultrahigh capacity (20 mAh cm?2). Remarkably, the potassium metal anode exhibits an unprecedented cycle life (over 1000 cycles, over 2000 h) at a high current density of 5 mA cm?2 and a desirable areal capacity of 4 mAh cm?2. Dendrite‐free morphology in carbon‐fiber and carbon‐black‐based ASEI for potassium metal anodes, which indicates a broader promise of this approach, is also observed.  相似文献   

18.
The combination of high‐capacity anodes and high‐voltage cathodes has garnered a great deal of attention in the pursuit of high‐energy‐density lithium‐ion batteries. As a facile and scalable electrode‐architecture strategy to achieve this goal, a direct one‐pot decoration of high‐capacity silicon (Si) anode materials and of high‐voltage LiCoO2 (LCO) cathode materials is demonstrated with colloidal nanoparticles composed of electroconductive antimony‐doped tin oxide (ATO). The unusual ATO nanoparticle shells enhance electronic conduction in the LCO and Si electrode materials and mitigate unwanted interfacial side reactions between the electrode materials and liquid electrolytes. The ATO‐coated LCO materials (ATO‐LCO) enable the construction of a high‐mass‐loading cathode and suppress the dissolution of cobalt and the generation of by‐products during high‐voltage cycling. In addition, the ATO‐coated Si (ATO‐Si) anodes exhibit highly stable capacity retention upon cycling. Integration of the high‐voltage ATO‐LCO cathode and high‐capacity ATO‐Si anode into a full cell configuration brings unprecedented improvements in the volumetric energy density and in the cycling performance compared to a commercialized cell system composed of LCO/graphite.  相似文献   

19.
A novel combination of hard carbon anode sodium pre‐loading and a tailored electrolyte is used to prepare room temperature sodium‐sulfur full cell batteries. The electrochemical loading with sodium ions is realized in a specific mixture of diethyl carbonate, ethylene carbonate, and fluoroethylene carbonate electrolyte in order to create a first solid electrolyte interface (SEI) on the anode surface. Combining such anodes with a porous carbon/sulfur composite cathode results in full cells with a significantly decreased polysulfide shuttle when compared to half cells combined with metallic sodium anodes. Further optimization involves the use of Na2S/P2S5 doped tetraethylene glycol dimethyl ether based electrolyte in the full cell for the formation of a second SEI, reducing polysulfide shuttle even further. More importantly, the electrochemical discharge processes in the cell are improved by adding this dissolved complexation agent to the electrolyte. As a result of this combination sodium‐sulfur cells with tailored cathode materials and electrolytes can achieve high discharge capacities up to 980 mAh g?1sulfur and 1000 cycles with 200 mAh g?1sulfur remaining capacity, at room temperature.  相似文献   

20.
Silicon‐based anodes with high theoretical capacity have intriguing potential applications for next‐generation high‐energy lithium‐ion batteries, but suffer from huge volumetric change that causes pulverization of electrodes. Rational design and construction of effective electrode structures combined with versatile binders remain a significant challenge. Here, a unique natural binder of konjac glucomannan (KGM) is developed and an amorphous protective layer of SiO2 is fabricated on the surface of Si nanoparticles (Si@SiO2) to enhance the adhesion. Benefiting from a plethora of hydroxyl groups, the KGM binder with inherently high adhesion and superior mechanical properties provides abundant contact sites to active materials. Molecular mechanics simulations and experimental results demonstrate that the enhanced adhesion between KGM and Si@SiO2 can bond the particles tightly to form a robust electrode. In addition to bridging KGM molecules, the SiO2‐functionalized surface may serve as a buffer layer to alleviate the stresses of Si nanoparticles resulting from the volume change. The as‐fabricated KGM/Si@SiO2 electrode exhibits outstanding structural stability upon long‐term cycles. A highly reversible capacity of 1278 mAh g?1 can be achieved over 1000 cycles at a current density of 2 A g?1, and the capacity decay is as small as 0.056% per cycle.  相似文献   

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