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Sodium-ion batteries (SIBs) are currently the most promising candidates for large-scale energy storage devices owing to their low cost and abundant resources. Titanium-based layered oxides have attracted widespread attention as promising anode materials due to delivering a safe potential of about 0.7 V (vs Na

Carbon-coated SiO

Red phosphorus (RP) as the anode material for the sodium-ion battery (SIB) possesses a high energy density, but the poor electronic conductivity and huge volume change during Na+ insertion/extraction restrict its application. In this work, the edible fungus slag-derived porous carbon (PC) is adopted as a carbon matrix to combine with RP to form PC@RP composites through a facile vaporization-condensation approach. The conductive porous carbon architecture improves the transfer of electron and Na+ in the composite. The robust carbon framework together with the chemical bonding between PC and RP effectively buffer the huge volumetric change of RP. As a result, the PC@RP composite material delivers a specific capacity of 655.1 mA h g-1 at 0.1 A g-1 with a capacity retention of 87% after 100 charging/discharging cycles. In particular, the full SIB assembled with P2-Na2/3Ni1/3Mn1/3Ti1/3O2 as the cathode material and PC@RP as the anode material exhibits a specific capacity of 77.3 mA h g-1 (based on the mass of cathode material) at 0.5 C, and 85% capacity is retained after 100 charging/discharging cycles.

Lithium (Li) metal is one of the most promising anodes for the high-energy density lithium batteries. Nevertheless, it is still a great challenge to construct a dendrite-free Li anode with stable solid electrolyte interphase (SEI) by adopting environmentally friendly approaches. Herein, a green artificial Li polylactic acid (LiPLA) SEI layer with biodegradability and highly rebound resilience is fabricated via an

Silicon-based electrodes are promising and appealing for futuristic Li-ion batteries because of their high theoretical specific capacity. However, massive volume change of silicon upon lithiation and delithiation, accompanied by continual formation and destruction of the solid-electrolyte interface (SEI), leads to low Coulombic efficiency. Prelithiation of Si-based anode is regarded as an effective way for compensating for the loss of Li

The development of highly efficient and stable cathodes for sodium-ion batteries (SIBs) is strategically critical to achieving large-scale electrical energy storage. Creating air-stable and high-voltage layered cathodes for sodium-ion full batteries still remains a challenge. Herein, we describe a rational design and preparation of a stable P3-Na2/3Ni1/4Mg1/12Mn2/3O2 cathode. The cathode displays a satisfactory working voltage of 3.6 V and excellent cyclic stability over 100 cycles at a 1 C rate without obvious capacity fading. The results of ex situ X-ray diffraction (XRD) demonstrate that the P3-type structure is well retained even when charged to 4.4 V. Furthermore, the structural characterization by XRD Rietveld refinement, scanning electron microscopy, and electrochemical testing certifies that the cathode maintains its structure commendably even when soaked in water for 12 h. In particular, the P3- Na2/3Ni1/4Mg1/12Mn2/3O2∥hard carbon full battery exhibits a desired competitively high voltage of 3.45 V and an attractive energy density of up to 412.2 W h kg-1 based on the cathode. The comprehensive results achieved by the specially designed strategy provide guidance toward the exploration of stable cathodes in the application of SIBs as modern energy-storage devices.

Si has been recognized as a next-generation anode alternative to graphite for high-energy-density lithium-ion batteries. However, the most intractable problem of previous Si-based anodes is the relatively low compressive strength of particles because of excess voids and porous structures, thus leading to poor structural integrity and electrochemical performance under high pressure of the rolling procedure in practical application. Therefore, a rational design of robust Si/C microspheres with a compact nano/microstructure is an effective strategy to address the above-mentioned issues. In this ingenious structure, Si nanoparticles are homogeneously dispersed and anchored on flake graphite and then the composites self-assemble into microspheres via polycondensation and surface tension of pitch under high temperature and high pressure. Benefitting from this innovative approach and rational design, the obtained robust Si/C microspheres not only present high compressive property and high tap density (1.0 g cm-3) but also demonstrate high initial Coulombic efficiency (90.5%) and cycling stability with areal capacity (4 mA h cm-2) under a compaction density of 1.3 g cm-3. Furthermore, the full cell assembled with LiNi0.8Co0.1Mn0.1O2 and the resultant Si/C microsphere anode also displays good cycling performance and rate capabilities. Owing to these aspects, the proposed rational design of encapsulating Si nanoparticles in high-tap-density microspheres could be extended to load other nanomaterials for advanced batteries.

Catalytic efficiency is a crucial index for electrodes in flow batteries, and tremendous efforts have been devoted to exploring catalysts with as many reaction zones as possible. Nevertheless, the space between the reaction sites, especially for interstitial space utilization, is usually ignored and challengeable to exploit owing to the balance between the catalytic efficiency and structural stability. Herein, a three-dimensional conducting network was constructed via a nitrogen-rich carbon film-bridged graphite felt framework (GF@N-C) to maximize its electrocatalytic effectiveness toward redox species. As the electrode, GF@N-C exhibits a superior rate constant and catalytic efficiency at 370 mA cm

Interfacial problems, including interfacial stability and contact issues, severely plague the practical application of Li metal anodes. Here we report an interfacial regulation strategy that stabilizes the Li metal-gel electrolyte interface through in situ constructing a stable solid electrolyte interphase (SEI) layer. By stabilizing the interface of Li metal anodes, the gel electrolyte enables dendrite-free morphology and high plating/stripping efficiency. A systematic analysis further confirms that the formed SEI layer is responsible for homogeneous deposition and stable cycling performance. Benefiting from the interfacial stability between electrodes and electrolytes, the lifespan of Li metal batteries is extended.

Red phosphorus is appealing for anode use in sodium-ion batteries. However, the synthesis of electrochemically stable red P anodes remains challenging due to a notable volume variation upon (de)sodiation, and limited synthetic methods arising from the low ignition and sublimation temperatures. To address the above problems, we herein successfully develop an industrially adaptable process for scalable synthesis of affordable phosphorus/carbon (APC) anode materials with an excellent electrochemical performance at a significantly reduced cost. The key to our success is a delicately designed, self-organized, strongly interactive porous P/C structure filled with sodium alginate binder, which maintains the structural integrity of anode and enhances the electrical contact of red P upon its volume variation via a dual protection from porous structure and strong surface interactions. The APC anodes hence present ultrahigh initial Coulombic efficiency (86.2%), excellent cycling stability, and superior rate capability. The industrially adaptable process and excellent electrochemical performance endow the novel APC nano/microspheres with promising applications in high-performance Na-ion batteries.

Highly catalytic electrodes play a vital role in exploiting the capability of vanadium redox flow batteries (VRFBs), but they suffer from a tedious synthesis process and ambiguous interaction mechanisms for catalytic sites. Herein, a facile urea pyrolysis process was applied to prepare graphitic carbon nitride-modified graphite felt (GF@CN), and by the virtue of a density functional theory-assisted calculation, the electron-rich pyridinic nitrogen atom of CN granules is demonstrated as the adsorption center for redox species and plays the key role in improving the performance of VRFBs, with 800 cycles and an energy efficiency of 75% at 150 mA cm–2. Such experimental and computational collaborative investigations guide a realizable and cost-effective solution for other high-power flow batteries.

Li-rich layered materials have been considered as the most promising cathode materials for future high-energy-density lithium-ion batteries. However, they suffer from severe voltage decay upon cycling, which hinders their further commercialization. Here, we report a Li-rich layered material 0.5Li2MnO3·0.5LiNi0.8Co0.1Mn0.1O2 with high nickel content, which exhibits much slower voltage decay during long-term cycling compared to conventional Li-rich materials. The voltage decay after 200 cycles is 201 mV. Combining in situ X-ray diffraction (XRD), ex situ XRD, ex situ X-ray photoelectron spectroscopy, and scanning transmission electron microscopy, we demonstrate that nickel ions act as stabilizing ions to inhibit the Jahn-Teller effect of active Mn(3+) ions, improving d-p hybridization and supporting the layered structure as a pillar. In addition, nickel ions can migrate between the transition-metal layer and the interlayer, thus avoiding the formation of spinel-like structures and consequently mitigating the voltage decay. Our results provide a simple and effective avenue for developing Li-rich layered materials with mitigated voltage decay and a long lifespan, thereby promoting their further application in lithium-ion batteries with high energy density.

An optimized nanocarbon-sulfur cathode material with ultrahigh sulfur loading of up to 90 wt % is realized in the form of sulfur nanolayer-coated three-dimensional (3D) conducting network. This 3D nanocarbon-sulfur network combines three different nanocarbons, as follows: zero-dimensional carbon nanoparticle, one-dimensional carbon nanotube, and two-dimensional graphene. This 3D nanocarbon-sulfur network is synthesized by using a method based on soluble chemistry of elemental sulfur and three types of nanocarbons in well-chosen solvents. The resultant sulfur-carbon material shows a high specific capacity of 1115 mA h g(-1) at 0.02C and good rate performance of 551 mA h g(-1) at 1C based on the mass of sulfur-carbon composite. Good battery performance can be attributed to the homogeneous compositing of sulfur with the 3D hierarchical hybrid nanocarbon networks at nanometer scale, which provides efficient multidimensional transport pathways for electrons and ions. Wet chemical method developed here provides an easy and cost-effective way to prepare sulfur-carbon cathode materials with high sulfur loading for application in high-energy Li-S batteries.

To exploit the high energy density of lithium-sulfur batteries, porous carbon materials have been widely used as the host materials of the S cathode. Current studies about carbon hosts are more frequently focused on the design of carbon structures rather than modification of its properties. In this study, we use boron-doped porous carbon materials as the host material of the S cathode to get an insightful investigation of the effect of B dopant on the S/C cathode. Powder electronic conductivity shows that the B-doped carbon materials exhibit higher conductivity than the pure analogous porous carbon. Moreover, by X-ray photoelectron spectroscopy, we prove that doping with B leads to a positively polarized surface of carbon substrates and allows chemisorption of S and its polysulfides. Thus, the B-doped carbons can ensure a more stable S/C cathode with satisfactory conductivity, which is demonstrated by the electrochemical performance evaluation. The S/B-doped carbon cathode was found to deliver much higher initial capacity (1300 mA h g(-1) at 0.25 C), improved cyclic stability, and rate capability when compared with the cathode based on pure porous carbon. Electrochemical impedance spectra also indicate the low resistance of the S/B-doped C cathode and the chemisorption of polysulfide anions because of the presence of B. These features of B doping can play the positive role in the electrochemical performance of S cathodes and help to build better Li-S batteries.

A composited anode material with combined layered α-Fe2O3 nanodisks and reduced graphene oxide was produced by an in situ hydrothermal method for lithium-ion batteries. As thin as about 5-nm-thickness α-Fe2O3 nanosheets, open channels, and face-to-face tight contact with reduced graphene oxide via oxygen bridges made the composite have a good cyclability and rate performance, especially at high charge/discharge rates.