Fe/N/S-doped porous carbon nanotubes with efficient oxygen reduction reaction catalytic activity were prepared by making full use of the multifunctional roles of FeCl3.

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Batteries with fast charging capability are urgently needed to meet the rapidly increasing demand for energy storage devices.

Heteroatoms-doped 3D porous carbon materials have been synthesized by utilizing hydroxyapatite in pig bones as self-template and used as electrode materials for symmetric supercapacitors, which exhibit ultra-high energy density both...

A facile electrostatic self-assembly followed by annealing strategy is presented to fabricate Fe 2 O 3 quantum dots embedded nitrogendoped 3D porous carbon (Fe 2 O 3 QDs/3DNPC) as anode material for lithium ion battery. The ultra-small Fe 2 O 3 QDs (3∼5 nm) are evenly distributed in the carbon matrix after high-temperature calcination, avoiding the obvious agglomeration that usually occurs at high temperature. At the same time, due to the involvement of Fe 2 O 3 QDs, the structure of carbon materials also changed accordingly, e.g., the interlayer spacing of carbon and disorder degree increased. In this way, lithium ions cannot only rapidly transfer between carbon layers, but also react more rapidly with Fe 2 O 3 nanoparticles. On the other hand, 3DNPC can accommodate the volume expansion of Fe 2 O 3 QDs and effectively prevent Fe 2 O 3 QDs from aggregating during charge and discharge processes. Due to its unique structure, Fe 2 O 3 QDs/3DNPC exhibits a high capacity of 531 mAh g −1 at 0.2 A g −1 and ultra-high rate performance of 211 mAh g −1 even at 20 A g −1 after 1000 cycles. Moreover, this composite also shows an outstanding cycling performance (almost no capacity fading after cycling 1000 times at current densities of 2 A g −1 10 A g −1 and 20 A g −1 ).

Heterojunctions are a promising class of materials for high‐efficiency bifunctional oxygen electrocatalysts in both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, the conventional theories fail to explain why many catalysts behave differently in ORR and OER, despite a reversible path (*O2⇋*OOH⇋*O⇋*OH). This study proposes the electron‐/hole‐rich catalytic center theory (e/h‐CCT) to supplement the existing theories, it suggests that the Fermi level of catalysts determines the direction of electron transfer, which affects the direction of the oxidation/reduction reaction, and the density of states (DOS) near the Fermi level determines the accessibility for injecting electrons and holes. Additionally, heterojunctions with different Fermi levels form electron‐/hole‐rich catalytic centers near the Fermi levels to promote ORR/OER, respectively. To verify the universality of the e/h‐CCT theory, this study reveals the randomly synthesized heterostructural Fe3N‐FeN0.0324 (FexN@PC with DFT calculations and electrochemical tests. The results show that the heterostructural F3N‐FeN0.0324 facilitates the catalytic activities for ORR and OER simultaneously by forming an internal electron‐/hole‐rich interface. The rechargeable ZABs with FexN@PC cathode display a high open circuit potential of 1.504 V, high power density of 223.67 mW cm−2, high specific capacity of 766.20 mAh g−1 at 5 mA cm−2, and excellent stability for over 300 h.