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A novel and facile strategy for fabricating red phosphorus@nitrogen doped graphene/carbon nanotube aerogel (P@NGCA) is proposed as a free-standing anode for high energy sodium-ion batteries. Owing to an optimized structure of red P uniformly confined in porous NGCA with high conductivity and mechanical stability, the free-standing P@NGCA anode exhibits outstanding sodium storage performance with a high areal capacity of 3.3 mA h cm−2 and superior initial Coulombic efficiency of 80%. [ABSTRACT FROM AUTHOR]

A novel design strategy for synthesizing hard carbon microspheres (HCMs) from a single source of sodium lignin sulfonate is proposed for a practical anode material of sodium-ion batteries. The HCM has an optimized microstructure, including an enlarged interlayer spacing and few defects, along with a low specific surface area. As an anode material of sodium-ion batteries, HCM is highly promising for practical applications because of its high capacity and reversibility. [ABSTRACT FROM AUTHOR]

Owing to the abundant resource and tunable structure, amorphous carbon materials have been widely studied as anode for alkali-metal ion batteries. However, it is still a huge space to promote their electrochemical performance for potassium ion batteries (PIBs), especially rate capability, because of the sluggish kinetics of potassium ions. In this work, 3D amorphous carbon with nitrogen and oxygen dual doping (N/O-3DC) is elaborately designed and facilely synthesized for high performance PIBs. Benefit from the synergistic effect of structural advantages, N/O-3DC electrode delivers a high reversible capacity (345 mA h g−1 at 0.03 A g−1), excellent rate performance (132 mA h g−1 at 9.6 A g−1) and ultralong lifespan (0.02% capacity decay per cycle over 1000 cycles at 3 A g−1). Combined with control experiment and structural characterization, it demonstrates the interaction between introduction of heteroatoms, construction of 3D open pore network and tailored microstructure, obtaining more active sites and enlarged interlayer spacing. Kinetic analysis and density functional theory calculations reveal dual N/O doping can not only facilitate the adsorption/desorption of K+ and elevate electronic conductivity, but also reduce energy barrier for K+ diffusion, hence promote the reaction kinetics. This work presents an appealing development of high performance carbon anode with multi-strategy coupling for PIBs. [Display omitted] • The N/O-3DC is obtained via a green approach originating from low-cost protein and facile NaCl template. • The structure design of N/O-3DC creates synergy effect for fast and stable potassium storage. • The N/O-3DC anode exhibits the superior rate performance. • The kinetic analysis and density functional theory calculations illuminate the electrochemical mechanism. [ABSTRACT FROM AUTHOR]