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Fe7S8 as a conversion‐type anode shows high capacity in lithium‐ion batteries (LIBs). Nevertheless, the sluggish ion transport rate, low electron conduction behavior, and large volume change upon cycling limit its applications in fast‐charging wide‐temperature‐range LIBs. Here, a simple hydrothermal and subsequent solid‐phase high‐pressure sulfidation route is proposed to synthesize a hollow Fe7S8/N‐doped C microsphere structure. The hollow space is enveloped by the spheres’ shell consisting of ultrafine Fe7S8 nanocrystals (≈8 nm) embedded into N‐doped C matrix, which enhances ion transport and electrical conduction, and accommodates the volume expansion of Fe7S8. Remarkably, in situ magnetometry reveals that spin‐polarized surface capacitance occurs during the stage of conversion reaction, in which the formed Fe and Li2S act as electrons and ions acceptor, respectively, to construct space charge zone at their interfaces, thus enhancing lithium transport and storage. Accordingly, the hollow microspheres show high gravimetric energy density and outstanding fast‐charging capability along with excellent cycling stability in Ah‐level pouch cells operating from ‐40 to 60 °C. For the first time, this work confirms the effectiveness of spin‐polarized surface capacitance effect on enhancing ion storage and transport in fast‐charging wide‐temperature‐range LIBs. [ABSTRACT FROM AUTHOR]

The germanium (Ge) anode attains wide attention in lithium‐ion batteries because of its high theoretical volumetric capacity (8646 mAh cm−3). However, the huge volume expansion (≈230%) results in its poor electrochemical performances. The strategies reported in the literature to solve the issue often cause a low packing density, lowering the volumetric capacity. Here, a pressure‐induced route is proposed to fabricate a Ge architecture, in which nano‐sized Ge (≈15 nm) is encapsulated by robust TiO2 and highly conductive carbon, which offer the advantages of a low stress–strain characteristic, low volume expansion in thickness change, high electrical conductivity (463.2 S m−1), high Li‐ion diffusion coefficient (9.55 × 10−9–8.51 × 10−12 cm2 s−1), and high tapping density (1.79 g cm−3). As a result, the dense architecture obtains outstanding volumetric capacities of 3559.8 mAh cm−3 at 0.1 A g−1 and 2628.2 mAh cm−3 at 20 A g−1, along with excellent cycling life over 5000 cycles at 10 A g−1. Remarkably, the full cell achieves a high volumetric energy density of 1760.1 Wh L−1, along with impressive fast‐charging performances and long cycling life. This work provides a new synthesis strategy and deep insight into the design of high‐volumetric capacity alloy‐based lithium‐ion‐battery anodes. [ABSTRACT FROM AUTHOR]

Silicon (Si) is widely used as a lithium‐ion‐battery anode owing to its high capacity and abundant crustal reserves. However, large volume change upon cycling and poor conductivity of Si cause rapid capacity decay and poor fast‐charging capability limiting its commercial applications. Here, we propose a multilevel carbon architecture with vertical graphene sheets (VGSs) grown on surfaces of subnanoscopically and homogeneously dispersed Si–C composite nanospheres, which are subsequently embedded into a carbon matrix (C/VGSs@Si–C). Subnanoscopic C in the Si–C nanospheres, VGSs, and carbon matrix form a three‐dimensional conductive and robust network, which significantly improves the conductivity and suppresses the volume expansion of Si, thereby boosting charge transport and improving electrode stability. The VGSs with vast exposed edges considerably increase the contact area with the carbon matrix and supply directional transport channels through the entire material, which boosts charge transport. The carbon matrix encapsulates VGSs@Si–C to decrease the specific surface area and increase tap density, thus yielding high first Coulombic efficiency and electrode compaction density. Consequently, C/VGSs@Si–C delivers excellent Li‐ion storage performances under industrial electrode conditions. In particular, the full cells show high energy densities of 603.5 Wh kg−1 and 1685.5 Wh L−1 at 0.1 C and maintain 80.7% of the energy density at 3 C. [ABSTRACT FROM AUTHOR]

Highlights: This study introduces an innovative 3D-printed electrolyte with vertically aligned ion transport network, which contains well-dispersed nanoscale Ta-doped Li7La3Zr2O12 in a poly(ethylene glycol) diacrylate matrix. The 3DSE architecture enables efficient ion transport across the Li/electrolyte and electrolyte/cathode interfaces, which allows for increased active material mass loading and enhanced interfacial adhesion. The p-3DSE Li symmetric cell displays an impressive critical current density value of 1.92 mA cm−2 and stable operation for 2600 h at room temperature. Full cells using p-3DSE achieve notable areal capacities. Improving the long-term cycling stability and energy density of all-solid-state lithium (Li)-metal batteries (ASSLMBs) at room temperature is a severe challenge because of the notorious solid–solid interfacial contact loss and sluggish ion transport. Solid electrolytes are generally studied as two-dimensional (2D) structures with planar interfaces, showing limited interfacial contact and further resulting in unstable Li/electrolyte and cathode/electrolyte interfaces. Herein, three-dimensional (3D) architecturally designed composite solid electrolytes are developed with independently controlled structural factors using 3D printing processing and post-curing treatment. Multiple-type electrolyte films with vertical-aligned micro-pillar (p-3DSE) and spiral (s-3DSE) structures are rationally designed and developed, which can be employed for both Li metal anode and cathode in terms of accelerating the Li+ transport within electrodes and reinforcing the interfacial adhesion. The printed p-3DSE delivers robust long-term cycle life of up to 2600 cycles and a high critical current density of 1.92 mA cm−2. The optimized electrolyte structure could lead to ASSLMBs with a superior full-cell areal capacity of 2.75 mAh cm−2 (LFP) and 3.92 mAh cm−2 (NCM811). This unique design provides enhancements for both anode and cathode electrodes, thereby alleviating interfacial degradation induced by dendrite growth and contact loss. The approach in this study opens a new design strategy for advanced composite solid polymer electrolytes in ASSLMBs operating under high rates/capacities and room temperature. [ABSTRACT FROM AUTHOR]

Free‐standing and foldable electrodes with high energy density and long lifespan have recently elicited attention on the development of lithium‐ion batteries (LIBs) for flexible electronic devices. However, both low energy density and slow kinetics in cycling impede their practical applications. In this work, a free‐standing and binder‐free N, O‐codoped 3D vertical graphene carbon nanofibers electrode with ultra‐high silicon content (VGAs@Si@CNFs) is developed via electrospinning, subsequent thermal treatment, and chemical vapor deposition processes. The as‐prepared VGAs@Si@CNFs electrode exhibits excellent conductivity and flexibility because of the high graphitized carbon nanofiber network and abundant vertical graphene arrays. Such 3D all‐carbon architecture can be fabulous for providing a conductive and mechanically robust network, further improving the kinetics and restraining the volume expansion of Si NPs, especially with an ultra‐high Si content (>90 wt%). As a result, the VGAs@Si@CNFs composite demonstrates a superior specific capacity (3619.5 mAh g−1 at 0.05 A g−1), ultralong lifespan, and outstanding rate capability (1093.1 mAh g−1 after 1500 cycles at 8 A g−1) as a free‐standing anode for LIBs. It is believed that this work offers an exciting method for developing free‐standing and high‐energy‐density electrodes for other energy storage devices. [ABSTRACT FROM AUTHOR]

A goal of extreme fast charging less than 15 min recharge time while maintaining high energy density has been pursued to meet fast-charging and high-energy-density demand on lithium ion batteries used in electric vehicles, which is still a challenge. Here, in order to realize the goal vertical graphene sheets are grown on surface of graphite by thermal chemical vapor deposition. The vertical graphene sheets not only can greatly boost lithium-ion transport rate due to its intrinsically high electrical conductivity but also can significantly reduce tortuosity of lithium ion transport due to its highly preferential lithium-ion insertion paths. In half cells, the vertical graphene sheets/graphite can endure 3000 cycles in 3 min of charge time per cycle. More remarkably, a full cell with vertical graphene sheets/graphite anode and LiFePO 4 cathode exhibits an ultrahigh energy density of 312.1 Wh kg−1 in 10 min of charge time per cycle at 4 C, indicating that the vertical graphene sheets/graphite anode possesses ability of extreme fast charging while maintaining high energy density. Image 1 • Vertical graphene sheets (VGSs) grow on surface of graphite by CVD. • The VGSs greatly reduce tortuosity of lithium ion transport. • The VGSs/graphite shows extreme fast-charging capability in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Despite its high capacity as a promising candidate material for lithium‐ion battery anodes, SiOx (x < 2) has the limitation of low conductivity and large volume change during cycling of SiOx, leading to low lithium‐ion transport rate, electrode destruction, and thus poor lithium‐ion storage performance. Herein, a novel 3D vertical graphene@SiOx/B‐doped carbon (3DVG@SiOx/BC) composite microsphere with 3DVG grown on SiOBC microspheres prepared by the pyrolysis of liquid tris(trimethylsilyl) borate in a sealed vessel using thermal chemical vapor deposition is reported. SiOBC can be transformed into SiOx/BC with homogeneously dispersed subnanoscale SiOx and BC particles during heating. The subnanoscale BC particles in spheres and 3DVG surface provide a fast lithium‐ion transport path and a robust skeleton, with an ultrahigh lithium‐ion diffusion coefficient (1.7 × 10−9 cm2 s−1) and an ultralow volume change (13.8%). The 3DVG@SiOx/BC microspheres exhibit a high electrical conductivity (6.5 × 103 S m−1) and tap density (0.83 g cm−3) as well as a high capacity, long cycling life, and excellent rate capability as anodes in half/full cells. The full cell with LiCoO2 as the cathode shows a high gravimetric and volumetric energy density of 459.4 Wh kg−1 and 1167.9 Wh L−1, respectively. [ABSTRACT FROM AUTHOR]

Silicon (Si) anodes offer excellent lithium storage capacity for lithium‐ion batteries but face practical limitations due to significant volume expansion and low intrinsic electrical conductivity. These issues lead to side reactions that consume the electrolyte and impede ion‐electron transport, resulting in low areal loading (<2 mg cm⁻²) and restricted energy density. To address this, a scalable method is developed using spray drying of commercial graphite flakes (s‐Gr) and nanosilicon particles (n‐Si), followed by chemical vapor deposition to create microscale Si/C anodes (s‐Gr/n‐Si/VGs). Thin vertical graphene nanosheets (VGs) are grown on the surfaces and within the internal pores, forming a robust, micron‐sized Si/C spherical composite material. The VGs construct the conductive network, allowing the electrodes to operate at high areal loadings without pulverization and promoting LiF‐enriched solid electrolyte interphase for improved cycling stability. The s‐Gr/n‐Si/VGs maintain a capacity of 641.9 mAh g⁻¹ after 1000 cycles at 11.0 mg cm⁻², retaining 95.9% capacity. In pouch cells with NCM811 cathodes, the 5.0 Ah‐level cells achieved 80.0% capacity retention after 510 cycles at 1.0 C. This research provides a feasible pathway for manufacturing high‐performance, low‐cost, and scalable Si/C anodes suitable for high‐energy‐density lithium‐ion batteries. [ABSTRACT FROM AUTHOR]