Due to their high conductivity and low cost, carbon materials have attracted great attention in the field of energy storage, especially as anode material for sodium ion batteries. Current research focuses on introducing external defects through heteroatom engineering to improve the sodium storage performance of carbon materials. However, there is still a lack of systematic investigation of the effects of intrinsic defects prevalent in carbon materials on sodium storage performance. Herein, template‐assisted method was used to design carbon materials with different degrees of intrinsic defects and explore their sodium storage properties. The experimental results show that the intrinsic defects in the carbon materials facilitates the adsorption behavior of Na+ during the surface induction capacitance process. Among them, the best carbon anode material exhibits high reversible capacity (221 mAh g−1 at 1 A g−1) and excellent rate performance. In addition, the density functional theory calculations also show that the existence of intrinsic defects can optimize the distribution of electron density, thereby increasing the Na‐adsorption capacity. This work makes an important contribution to understanding the role of intrinsic defects in the sodium storage performance of carbon materials.

Heteroatom doping plays a significant role in optimizing the catalytic performance of electrocatalysts. However, research on heteroatom doped electrocatalysts with abundant defects and well-defined morphology remain a great challenge. Herein, a class of defect-engineered nitrogen-doped Co 3 O 4 nanoparticles/nitrogen-doped carbon framework (N-Co 3 O 4 @NC) strongly coupled porous nanocubes, made using a zeolitic imidazolate framework-67 via a controllable N-doping strategy, is demonstrated for achieving remarkable oxygen evolution reaction (OER) catalysis. X-ray photoelectron spectroscopy, X-ray absorption fine structure, and electron spin resonance results clearly reveal the formation of a considerable amount of nitrogen dopants and oxygen vacancies in N-Co 3 O 4 @NC. The defect engineering of N-Co 3 O 4 @NC makes it exhibit an overpotential of only 266 mV to reach 10 mA cm −2 , a low Tafel slope of 54.9 mV dec −1 and superior catalytic stability for OER, which is comparable to that of commercial RuO 2 . Density functional theory calculations indicate N-doping could promote catalytic activity via improving electronic conductivity, accelerating reaction kinetics, and optimizing the adsorption energy for intermediates of OER. Interestingly, N-Co 3 O 4 @ NC also shows a superior oxygen reduction reaction activity, making it a bifunctional electrocatalyst for zinc-air batteries. The zinc-air battery with the N-Co 3 O 4 @NC cathode demonstrates superior efficiency and durability, showing the feasibility of N-Co 3 O 4 /NC in electrochemical energy devices.

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1T-phase MoS2 is a promising electrode material for electrochemical energy storage due to its metallic conductivity, abundant active sites, and high theoretical capacity. However, because of the habitual conversion of metastable 1T to stable 2H phase via restacking, the poor rate capacity and cycling stability at high current densities hamper their applications. Herein, a synergetic effect of electron-injection engineering and atomic-interface engineering is employed for the formation and stabilization of defected 1T-rich MoS2 nanoflowers. The 1T-rich MoS2 and carbon monolayers are alternately intercalated with each other in the nanohybrids. The metallic 1T-phase MoS2 and conductive carbon monolayers are favorable for charge transport. The expanded interlayer spacing ensures fast electrolyte diffusion and the decrease of the ion diffusion barrier. The obtained defected 1T-rich MoS2/m-C nanoflowers exhibit high Na-storage capacity (557 mAh g–1 after 80 cycles at 0.1 A g–1), excellent rate capacity (411 mAh g–1 at 10 A g–1), and long-term cycling performance (364 mAh g–1 after 1000 cycles at 2 A g–1). Furthermore, a Na-ion full cell composed of the 1T-rich MoS2/m-C anode and Na3V2(PO4)3/C cathode maintains excellent cycling stability at 0.5 A g–1 during 400 cycles. Theoretical calculations are also performed to evaluate the phase stability, electronic conductivity, and Na+ diffusion behavior of 1T-rich MoS2/m-C. The energy storage performance demonstrates its excellent application prospects.

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