Boron-doped graphite was prepared by the heat treatment of coke using B₄C powder as a graphitization catalyst to investigate the effects of the substitutional boron atoms on the interlayer spacing of graphite. Boron atoms can be successfully incorporated into the lattice of graphite by heat treatment, resulting in a reduction in the interlayer spacing of graphite to a value close to that of ideal graphite (0.3354 nm). With an increase in the catalyst mass ratio, the content of substituted boron in the samples increased significantly, causing a decrease in the interlayer spacing of the boron-doped graphite. Density functional theory calculations suggested that the effects of the substitutional boron atoms on the interlayer spacing of the graphite may be attributed to the transfer of Π electrons between layers, the increase in the electrostatic surface potential of the carbon layer due to the electron-deficient nature of boron atoms, and Poisson contraction along the c-axis.

Lithium metal anodes, acting as a competitive candidate for the construction of high-energy-density rechargeable batteries, have drawn tremendous attention in both academia and industry. However, the uncontrollable growth of lithium dendrites and dramatic volume changes during lithium plating/stripping prevent their practical application. In this work, we demonstrate tent-like nitrogen-doped porous carbon microcavities decorated on carbon cloth (NPCM@CC) which could guide the Li ion flux, reduce the nucleation overpotential and decrease local current density, thus regulating the nucleation and growth behavior of metallic lithium. Consequently, the assembled cells based on NPCM@CC display remarkable electrochemical performances as reflected by an extremely high coulombic efficiency (99.1% at 4 mA h cm⁻²), excellent long-term cycling stability (over 4200 and 1200 h at 1 and 2 mA cm⁻², respectively), and an ultralow overpotential value of 46 mV at a current density up to 10 mA cm⁻².

Li metal is an attractive anode material for electrochemical energy storage. However, the growth of Li dendrites accompanied with infinity-dimension changes, which leads to decreased coulombic efficiency and Li utilization, has long hampered practical application in rechargeable Li-metal batteries. Herein, a 3D ZIF-8@RGO scaffold with in-situ-formed abundant N/Zn sites after a convenient carbonization strategy is successfully demonstrated as both current collector and host material for Li metal anodes. Preferential Li deposition is predominantly accommodated into the 3D matrix free of dendrites by the synergetic effect of lithiophilic N/Zn nucleation sites and free-standing RGO with outstanding conductive properties. Profiting from the selective deposition and stable encapsulation, Li/ZIF-8@RGO anodes with preloading 5 mA h cm⁻² Li can run for 600 h without short circuit and deliver a promoted coulombic efficiency of ∼98.48% over 350 cycles. Moreover, the ZIF-8@RGO-based full cells exhibit exceptional cycling stability and rate capability.

Two isotropic pitches were prepared by air blowing and nitrogen distillation methods using ethylene tar (ET) as a raw material. The corresponding carbon fibers were obtained through conventional melt spinning, stabilization, and carbonization. The structures and properties of the resultant pitches and fibers were characterized, and their differences were examined. The results showed that the introduction of oxygen by the air blowing method could quickly increase the yield and the softening point of the pitch. Moreover, the air-blown pitch (ABP) was composed of aromatic molecules with linear methylene chains, while the nitrogen-distilled pitch (NDP) mainly contained polycondensed aromatic rings. This is because the oxygen-containing functional groups in the ABP could impede ordered stack of pitch molecules and led to a methylene bridge structure instead of an aromatic condensed structure as in the NDP. Meanwhile, the spinnability of the ABP did not decrease even though it contained 2.31 wt % oxygen. In contrast, the ABP had narrower molecular weight distribution, which contributed to better stabilization properties and higher tensile strength of the carbon fiber. The tensile strength of carbon fibers from the ABP reached 860 MPa with fiber diameter of about 10 μm, which was higher than the tensile strength of 640 MPa for the NDP-derived carbon fibers.