Carbonaceous materials are considered strong candidates as anode materials for sodium-ion batteries (SIBs), which are expected to play an indispensable role in the carbon-neutral era. Herein, novel braided porous carbon fibres (BPCFs) are prepared using the chemical vapour deposition (CVD) method. The BPCFs possess interwoven porous structures and abundant vacancies. The growth mechanism of the BPCFs can be attributed to the polycrystalline transformation of the nanoporous copper catalyst in the early stage of CVD process. Density functional theory calculations suggest that the Na + adsorption energies of the mono-vacancy edges of the BPCFs (−1.22 and −1.09 eV) are lower than that of an ideal graphene layer (−0.68 eV), clarifying in detail the adsorption-dominated sodium storage mechanism. Hence, the BPCFs as an anode material present an outstanding discharge capacity of 401 mAh g −1 at 0.1 A g−1 after 500 cycles. Remarkably, this BPCFs anode, under high-mass-loading of 5 mg cm−2, shows excellent long-term cycling ability with a reversible capacity of 201 mAh g −1 at 10 A g −1 over 1000 cycles. This study provided a novel strategy for the development of high-performance carbonaceous materials for SIBs.

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The high theoretical capacity of germanium (Ge) is considerably restricted in practical applications due to the low conductivity and large volume variation range. The complex preparation process will further hinder the development of Ge anodes in lithium-ion batteries. In this paper, the Ge/Cu3Ge/GeO2 composites with a continuous channel structure are composed of conductive Cu3Ge and high-capacity GeO2 dispersed in a Ge matrix, which were prepared by melt spinning, de-alloying, and oxidation in easy massive production. The optimized sample of D-Cu2Ge8-600 showed excellent cycling performance with a specific capacity of 875.7 mAh g–1 after 500 cycles at a current density of 0.1 A g–1. D-Cu2Ge8-600 also presents outstanding electrochemical performance in a full cell composed of commercial LiCoO2. The high lithium storage performance is inextricably attributed to that Cu3Ge and GeO2 allow Ge nanoparticles to be uniformly dispersed in a continuous channel structure providing volume space. Among them, the Cu3Ge phase acts as a conductive network. Concurrently, GeO2 improves the specific capacity of the whole electrode material. The easily prepared composites on a large scale could provide a novel route for future practical applications of Si- and Ge-based anode materials.

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