Low‐Temperature Growth of All‐Carbon Graphdiyne on a Silicon Anode for High‐Performance Lithium‐Ion Batteries

In situ weaving an all‐carbon graphdiyne coat on a silicon anode is scalably realized under ultralow temperature (25 °C). This economical strategy not only constructs 3D all‐carbon mechanical and conductive networks with reasonable voids for the silicon anode at one time but also simultaneously forms a robust interfacial contact among the electrode components. The intractable problems of the disintegrations in the mechanical and conductive networks and the interfacial contact caused by repeated volume variations during cycling are effectively restrained. The as‐prepared electrode demostrates the advantages of silicon regarding capacity (4122 mA h g^?1 at 0.2 A g^?1) with robust capacity retention (1503 mA h g^?1) after 1450 cycles at 2 A g^?1, and a commercial‐level areal capacity up to 4.72 mA h cm^?2 can be readily approached. Furthermore, this method shows great promises in solving the key problems in other high‐energy‐density anodes.     

Surface Coating Constraint Induced Anisotropic Swelling of Silicon in Si–Void@SiO x Nanowire Anode for Lithium‐Ion Batteries

Here a simple and an environmentally friendly approach is developed for the fabrication of Si–void@SiO_x nanowires of a high‐capacity Li‐ion anode material. The outer surface of the robust SiO_x backbone and the inside void structure in Si–void@SiO_x nanowires appropriately suppress the volume expansion and lead to anisotropic swelling morphologies of Si nanowires during lithiation/delithiation, which is first demonstrated by the in situ lithiation process. Remarkably, the Si–void@SiO_x nanowire electrode exhibits excellent overall lithium‐storage performance, including high specific capacity, high rate property, and excellent cycling stability. A reversible capacity of 1981 mAh g^?1 is obtained in the fourth cycle, and the capacity is maintained at 2197 mAh g^?1 after 200 cycles at a current density of 0.5 C. The outstanding overall properties of the Si–void@SiO_x nanowire composite make it a promising anode material of lithium‐ion batteries for the power‐intensive energy storage applications.     

Lithium–Graphite Paste: An Interface Compatible Anode for Solid‐State Batteries

All‐solid‐state batteries (ASSBs) with ceramic‐based solid‐state electrolytes (SSEs) enable high safety that is inaccessible with conventional lithium‐ion batteries. Lithium metal, the ultimate anode with the highest specific capacity, also becomes available with nonflammable SSEs in ASSBs, which offers promising energy density. The rapid development of ASSBs, however, is significantly hampered by the large interfacial resistance as a matched lithium/ceramic interface that is not easy to pursue. Here, a lithium–graphite (Li–C) composite anode is fabricated, which shows a dramatic modification in wettability with garnet SSE. An intimate Li–C/garnet interface is obtained by casting Li–C composite onto garnet‐type SSE, delivering an interfacial resistance as low as 11 Ω cm². As a comparison, pure Li/garnet interface gives a large resistance of 381 Ω cm². Such improvement can be ascribed to the experiment‐measured increased viscosity of Li–C composite and simulation‐verified limited interfacial reaction. The Li–C/garnet/Li–C symmetric cell exhibits stable plating/striping performance with small voltage hysteresis and endures a critical current density up to 1.0 mA cm^?2. The full cell paired with LiFePO₄ shows stable cycle performance, comparable to the cell with liquid electrolyte. The present work demonstrates a promising strategy to develop ceramic‐compatible lithium metal‐based anodes and hence low‐impedance ASSBs.     

A 3D and Stable Lithium Anode for High‐Performance Lithium–Iodine Batteries

Lithium metal is considered as the most promising anode material due to its high theoretical specific capacity and the low electrochemical reduction potential. However, severe dendrite problems have to be addressed for fabricating stable and rechargeable batteries (e.g., lithium–iodine batteries). To fabricate a high‐performance lithium–iodine (Li–I₂) battery, a 3D stable lithium metal anode is prepared by loading of molten lithium on carbon cloth doped with nitrogen and phosphorous. Experimental observations and theoretical calculation reveal that the N,P codoping greatly improves the lithiophilicity of the carbon cloth, which not only enables the uniform loading of molten lithium but also facilitates reversible lithium stripping and plating. Dendrites formation can thus be significantly suppressed at a 3D lithium electrode, leading to stable voltage profiles over 600 h at a current density of 3 mA cm^?2. A fuel cell with such an electrode and a lithium–iodine cathode shows impressive long‐term stability with a capacity retention of around 100% over 4000 cycles and enhanced high‐rate capability. These results demonstrate the promising applications of 3D stable lithium metal anodes in next‐generation rechargeable batteries.     

A Quadruple‐Hydrogen‐Bonded Supramolecular Binder for High‐Performance Silicon Anodes in Lithium‐Ion Batteries

With extremely high specific capacity, silicon has attracted enormous interest as a promising anode material for next‐generation lithium‐ion batteries. However, silicon suffers from a large volume variation during charge/discharge cycles, which leads to the pulverization of the silicon and subsequent separation from the conductive additives, eventually resulting in rapid capacity fading and poor cycle life. Here, it is shown that the utilization of a self‐healable supramolecular polymer, which is facilely synthesized by copolymerization of tert‐butyl acrylate and an ureido‐pyrimidinone monomer followed by hydrolysis, can greatly reduce the side effects caused by the volume variation of silicon particles. The obtained polymer is demonstrated to have an excellent self‐healing ability due to its quadruple‐hydrogen‐bonding dynamic interaction. An electrode using this self‐healing supramolecular polymer as binder exhibits an initial discharge capacity as high as 4194 mAh g⁻¹ and a Coulombic efficiency of 86.4%, and maintains a high capacity of 2638 mAh g⁻¹ after 110 cycles, revealing significant improvement of the electrochemical performance in comparison with that of Si anodes using conventional binders. The supramolecular binder can be further applicable for silicon/carbon anodes and therefore this supramolecular strategy may increase the choice of amendable binders to improve the cycle life and energy density of high‐capacity Li‐ion batteries.     

Graphene Caging Silicon Particles for High‐Performance Lithium‐Ion Batteries

Silicon holds great promise as an anode material for lithium‐ion batteries with higher energy density; its implication, however, is limited by rapid capacity fading. A catalytic growth of graphene cages on composite particles of magnesium oxide and silicon, which are made by magnesiothermic reduction reaction of silica particles, is reported herein. Catalyzed by the magnesium oxide, graphene cages can be conformally grown onto the composite particles, leading to the formation of hollow graphene‐encapsulated Si particles. Such materials exhibit excellent lithium storage properties in terms of high specific capacity, remarkable rate capability (890 mAh g^?1 at 5 A g^?1), and good cycling retention over 200 cycles with consistently high coulombic efficiency at a current density of 1 A g^?1. A full battery test using LiCoO₂ as the cathode demonstrates a high energy density of 329 Wh kg^?1.     

Dual‐Functionalized Double Carbon Shells Coated Silicon Nanoparticles for High Performance Lithium‐Ion Batteries

To address the challenge of huge volume change and unstable solid electrolyte interface (SEI) of silicon in cycles, causing severe pulverization, this paper proposes a “double‐shell” concept. This concept is designed to perform dual functions on encapsulating volume change of silicon and stabilizing SEI layer in cycles using double carbon shells. Double carbon shells coated Si nanoparticles (DCS‐Si) are prepared. Inner carbon shell provides finite inner voids to allow large volume changes of Si nanoparticles inside of inner carbon shell, while static outer shell facilitates the formation of stable SEI. Most importantly, intershell spaces are preserved to buffer volume changes and alleviate mechanical stress from inner carbon shell. DCS‐Si electrodes display a high rechargeable specific capacity of 1802 mAh g⁻¹ at a current rate of 0.2 C, superior rate capability and good cycling performance up to 1000 cycles. A full cell of DCS‐Si//LiNi_0.45Co_0.1Mn_1.45O₄ exhibits an average discharge voltage of 4.2 V, a high energy density of 473.6 Wh kg⁻¹, and good cycling performance. Such double‐shell concept can be applied to synthesize other electrode materials with large volume changes in cycles by simultaneously enhancing electronic conductivity and controlling SEI growth.     

Necklace‐Like Structures Composed of Fe3N@C Yolk–Shell Particles as an Advanced Anode for Sodium‐Ion Batteries

It is of great importance to develop cost‐effective electrode materials for large‐scale use of Na‐ion batteries. Here, a binder‐free electrode based on necklace‐like structures composed of Fe₃N@C yolk–shell particles as an advanced anode for Na‐ion batteries is reported. In this electrode, every Fe₃N@C unit has a novel yolk–shell structure, which can accommodate the volumetric changes of Fe₃N during the (de)sodiation processes for superior structural integrity. Moreover, all reaction units are threaded along the carbon fibers, guaranteeing excellent kinetics for the electrochemical reactions. As a result, when evaluated as an anode material for Na‐ion batteries, the Fe₃N@C nano‐necklace electrode delivers a prolonged cycle life over 300 cycles, and achieves a high C‐rate capacity of 248 mAh g^?1 at 2 A g^?1.     

Bioinspired,Spine‐Like,Flexible, Rechargeable Lithium‐Ion Batteries with High Energy Density

The rapid development of flexible and wearable electronics proposes the persistent requirements of high‐performance flexible batteries. Much progress has been achieved recently, but how to obtain remarkable flexibility and high energy density simultaneously remains a great challenge. Here, a facile and scalable approach to fabricate spine‐like flexible lithium‐ion batteries is reported. A thick, rigid segment to store energy through winding the electrodes corresponds to the vertebra of animals, while a thin, unwound, and flexible part acts as marrow to interconnect all vertebra‐like stacks together, providing excellent flexibility for the whole battery. As the volume of the rigid electrode part is significantly larger than the flexible interconnection, the energy density of such a flexible battery can be over 85% of that in conventional packing. A nonoptimized flexible cell with an energy density of 242 Wh L^?1 is demonstrated with packaging considered, which is 86.1% of a standard prismatic cell using the same components. The cell also successfully survives a harsh dynamic mechanical load test due to this rational bioinspired design. Mechanical simulation results uncover the underlying mechanism: the maximum strain in the reported design (≈0.08%) is markedly smaller than traditional stacked cells (≈1.1%). This new approach offers great promise for applications in flexible devices.     

Rationally Designed Silicon Nanostructures as Anode Material for Lithium‐Ion Batteries

Silicon (Si) is promising for high capacity anodes in lithium‐ion batteries due to its high theoretical capacity, low working potential, and natural abundance. However, there are two main drawbacks that impede its further practical applications. One is the huge volume expansion generating during lithiation and delithiation progresses, which leads to severe structural pulverization and subsequently rapid capacity fading of the electrode. The other is the relatively low intrinsic electronic conductivity, therefore, seriously impacting the rate performance. In the past decades, numerous efforts have been devoted for improving the cycling stability and rate capability by rational designs of different nanostructures of Si materials and incorporations with some conductive agents. In this review, the authors summarize the exciting recent research works and focus on not only the synthesis techniques, but also the composition strategies of silicon nanostructures. The advantages and disadvantages of the nanostructures as well as the perspective of this research field are also discussed. We aim to give some reference for engineering application on Si anodes in lithium ion batteries.