Correction: A hierarchical porous P-doped carbon electrode through hydrothermal carbonization of pomelo valves for high-performance supercapacitors.

[This corrects the article DOI: 10.1039/D0NA00211A.].

Correction: Bio-inspired hierarchical nanoporous carbon derived from water spinach for high-performance supercapacitor electrode materials.

[This corrects the article DOI: 10.1039/D1NA00636C.].

Correction: Effect of pomelo seed-derived carbon on the performance of supercapacitors.

[This corrects the article DOI: 10.1039/D0NA00778A.].

Correction: Celery-derived porous carbon materials for superior performance supercapacitors.

[This corrects the article DOI: 10.1039/D1NA00342A.].

The Enhancement Mechanism of Different Single-Transition Metal Atomic Catalysts/Sulfur Cathode on High-Performance of Li-S Batteries.

Materials with various single-transition metal atoms dispersed in nitrogenated carbons (M─N─C, M = Fe, Co, and Ni) are synthesized as cathodes to investigate the electrocatalytic behaviors focusing on their enhancement mechanism for performance of Li-S batteries. Results indicate that the order of both electrocatalytic activity and rate capacity for the M─N─C catalysts is Co > Ni > Fe, and the Co─N─C delivers the highest capacity of 1100 mAh g-1 at 1 C and longtime stability at a decay rate of 0.05% per cycle for 1000 cycles, demonstrating excellent battery performance. Theoretical calculations for the first time reveal that M─N─N─C catalysts enable direct conversion of Li2 S6 to Li2 S rather than Li2 S4 to Li2 S by stronger adsorption with Li2 S6 , which also has an order of Co > Ni > Fe. And Co─N─C has the strongest adsorption energy, not only rendering the highest electrocatalytic activity, but also depressing the polysulfides' dissolution into electrolyte for the longest cycle life. This work offers an avenue to design the next generation of highly efficient sulfur cathodes for high-performance Li-S batteries, while shedding light on the fundamental insight of single metal atomic catalytic effects on Li-S batteries.

Correction: A hierarchical integrated 3D carbon electrode derived from gingko leaves via hydrothermal carbonization of H3PO4 for high-performance supercapacitors.

[This corrects the article DOI: 10.1039/D3NA90045B.][This corrects the article DOI: 10.1039/D2NA00758D.].

Correction: A hierarchical integrated 3D carbon electrode derived from gingko leaves via hydrothermal carbonization of H3PO4 for high-performance supercapacitors.

[This corrects the article DOI: 10.1039/D2NA00758D.].

A hierarchical integrated 3D carbon electrode derived from gingko leaves via hydrothermal carbonization of H3PO4 for high-performance supercapacitors.

Electrochemical ultracapacitors derived from green and sustainable materials could demonstrate superior energy output and an ultra-long cycle life owing to large accessible surface area and obviously shortened ion diffusion pathways. Herein, we have established an efficient strategy to fabricate porous carbon (GLAC) from sustainable gingko leaf precursors by a facile hydrothermal activation of H3PO4 and low-cost pyrolysis. In this way, GLAC with a hierarchically porous structure exhibits extraordinary adaptability toward a high energy/power supercapacitor (∼709 F g-1 at 1 A g-1) in an aqueous electrolyte (1 M KOH). Notably, the GLAC-2-based supercapacitor displays an ultra-high stability of ∼98.24% even after 10 000 cycles (10 A g-1) and an impressive energy density as large as ∼71 W h kg-1 at a power density of 1.2 kW kg-1. The results provide new insights that the facile synthetic procedure coupled with the excellent performance contributes to great potential for future application in the electrochemical energy storage field.

Bio-inspired hierarchical nanoporous carbon derived from water spinach for high-performance supercapacitor electrode materials.

Due to various properties, green carbon nanomaterials with high specific surface area and environmentally friendly features have aroused extensive interest in energy storage device applications. Here, we report a facile, one-step carbonization of water spinach to synthesize porous carbon that exhibits a high specific surface area of ∼1559 m2 g-1, high specific capacitance (∼1191 F g-1 at 1 A g-1), a low intercept (0.9 Ω), outstanding rate capability and superior cycling stability (94.3% capacitance retention after 10 000 cycles). Moreover, the assembled symmetric cell delivers a high energy density of ∼85 W h kg-1 at 1200 W kg-1 and ultra-high stability (loss of 6.8% after 10 000 cycles). An energy density of 49 W h kg-1 could also be achieved even with a power density of up to 24 kW kg-1, which indicates that this material could be a promising candidate for future applications in aqueous-based supercapacitors.

Oxygen-defect-rich 3D porous cobalt-gallium layered double hydroxide for high-performance supercapacitor application.

In this work, oxygen-defect-rich, three-dimensional (3D) cobalt-gallium layered double hydroxides (Co0.50-Ga0.50-LDH) assembled by porous and ultrathin nanosheets are prepared by a simple one-step strategy. Briefly, an aqueous solution containing Co2+ and Ga3+ is quickly pouring into the aqueous solution of hexamethylenetetramine, the state-of-the-art LDH was obtained followed by a mild and fast hydrothermal reaction. This mild and rapid synthesis strategy introduces a large number of pores into the ultrathin LDH nanosheets, resulting in a high concentration of oxygen vacancies in the Co0.50-Ga0.50-LDH, and the concentration of oxygen vacancies can be arbitrarily modulated, which has been corroborated by X-ray photoelectron spectroscopy and electron spin resonance measurements. The synergistic effect of the oxygen vacancy and the introduced Ga ions in the LDH nanosheets enhances the adsorption of the LDH nanosheets on OH-, endowing Co0.50-Ga0.50-LDH with outstanding performance for the supercapacitor application. Co0.50-Ga0.50-LDH offers a high specific capacity (0.62C·cm-2) at 10 mV·s-1 and extraordinary cycling stability. An aqueous asymmetric supercapacitor (ASC) constructed with Co0.50-Ga0.50-LDH and activated carbon (AC) materials exhibits high energy density and a long lifespan. This result encourages the wide application of porous ultrathin LDH nanosheets in energy storage, catalysis and light response.

A Battery-Like Self-Selecting Biomemristor from Earth-Abundant Natural Biomaterials.

Using the earth-abundant natural biomaterials to manufacture functional electronic devices meets the sustainable requirement of green electronics, especially for the practical application of memristors in data storage and neuromorphic computing. However, the sneak currents flowing though the unselected cells in a large-scale cross-bar memristor array is one of the major problems which need to be tackled. The self-selecting memristors can solve the problem to develop compact and concise integrated circuits. Here, a sustainable natural biomaterial (anthocyanin, C15H11O6) extracted from plant tissue is demonstrated for ions and electron transport. The capacitive-coupled memristive behavior of as-prepared bioelectronic device can be significantly modulated by diethylmethyl(2-methoxyethyl)ammoium bis(trifluoromethylsulfonyl)imide (DEME-TFSI) ionic liquid (IL). Furthermore, graphene was inserted into biomaterial matrix to manipulate the memristive effects by graphene protonation. This results in a battery-like self-selective memristive effect. This phenomenon is explained by a physical model and density functional theory (DFT) based first-principles calculations. Finally, the self-selective behavior was applied in 0T-1R array configuration, which indicates the battery-like self-selecting biomemristor has potential applications in the brain-inspired computing, data storage systems, and high-density device integration.

Celery-derived porous carbon materials for superior performance supercapacitors.

Supercapacitors are of paramount importance for next-generation applications, demonstrating high energy output and an ultra-long cycle life, and utilizing green and sustainable materials. Herein, we utilize celery, a common biomass from vegetables, by a facile low-cost pyrolysis and activation method for use in high-voltage, high-energy, and high-power supercapacitors. The as-synthesized hierarchically porous carbon materials with a high surface area of 1612 m2 g-1 and a large quantity of nitrogen and phosphorus heteroatoms exhibit a high specific capacitance of 1002.80 F g-1 at 1 A g-1 and excellent cycling stability of 95.6% even after 10 000 cycles (10 A g-1) in aqueous electrolytes. Moreover, the assembled symmetric cell delivers a high energy density of 32.7 W h kg-1 at 1200 W kg-1 and an ultra-high stability (loss of 4.8% after 10 000 cycles). Therefore, the outstanding electrochemical performance of the materials will be of use in the development of high-performance, green supercapacitors for advanced energy storage systems.

Effect of pomelo seed-derived carbon on the performance of supercapacitors.

Electrochemical ultracapacitors derived from green and sustainable materials could demonstrate superior energy output and an ultra-long cycle life, which could contribute to next-generation applications. Herein, we utilize pomelo seeds, a bio-waste from pomelo, in high-energy and high-power supercapacitors by a facile low-cost pyrolysis and activation method. The as-synthesized hierarchically porous carbon is surface-engineered with a large quantity of nitrogen and sulfur heteroatoms to give a high specific capacitance of ∼845 F g-1 at 1 A g-1. An ultra-high stability of ∼93.8% even after 10 000 cycles (10 A g-1) is achieved at room temperature. Moreover, a maximum energy density of ∼85 W h kg-1 at a power density of 1.2 kW kg-1 could be achieved in 1.2 V aqueous symmetrical supercapacitors. The results provide new insights that will be of use in the development of high-performance, green supercapacitors for advanced energy storage systems.

A hierarchical porous P-doped carbon electrode through hydrothermal carbonization of pomelo valves for high-performance supercapacitors.

Porous carbon materials are synthesized from pomelo valves by the hydrothermal activation of H3PO4 followed by simple carbonization. The as-synthesized hierarchically porous carbon electrode exhibits a high specific capacitance of 966.4 F g-1 at 1 A g-1 and an ultra-high stability of 95.6% even after 10 000 cycles. Moreover, the supercapacitor also demonstrates a maximum energy of 36.39 W h kg-1 and a maximum power of 33.33 kW kg-1 with an energy retention of 25.56 W h kg-1, which paves the way for the development of high-performance, green supercapacitors for advanced energy storage systems.

Evolution map of the memristor: from pure capacitive state to resistive switching state.

Memristors possess great application prospects in terabit nonvolatile storage devices, memory-in-logic algorithmic chips and bio-inspired artificial neural network systems. However, "what is the origin state of the memristor?" has remained an unanswered question for half a century. While many applications rely on the memristor, its origin state is becoming a fundamental issue. Herein, we reveal a new state, the pure capacitance state (PCS), which occurs before the memristor is triggered, and the origin state of the memristor can be verified in the memory cells through controlling the ambience parameters. Discovery of the PCS, a missing earlier stage of the memristor, completes the whole evolution map of the memristor from the very beginning to the final developed state.

3D honeycomb-like carbon foam synthesized with biomass buckwheat flour for high-performance supercapacitor electrodes.

A facile, one-step carbonization of buckwheat flour is innovated to synthesize honeycomb-like porous carbon, which exhibits specific capacitance (767 F g-1 at 1 A g-1) and stability with a retention of up to 92.6% after 10 000 cycles.

Atomic matching catalysis to realize a highly selective and sensitive biomimetic uric acid sensor.

A main challenge for biomimetic non-enzyme biosensors is to achieve high selectivity. Herein, an innovative biomimetic non-enzyme sensor for electrochemical detection of uric acid (UA) with high selectivity and sensitivity is realized by growing Prussian blue (PB) nanoparticles on nitrogen-doped carbon nanotubes (N-doped CNTs). The enhancement mechanism of the biomimetic UA sensor is proposed to be atomically matched active sites between two reaction sites (oxygen atoms of 2, 8-trione, 6.9 Å) of UA molecule and two redox centers (FeII on the diagonal, 7.2 Å) of PB. Such an atomically matching manner not only promotes strong adsorption of UA on PB but also selectively enhances electron transfer between reaction sites of UA and active FeII centers of PB. This biomimetic UA sensor can offer great selectivity to avoid interferences from other oxidative and reductive species, showing excellent selectivity. An electrochemical biomimetic sensor based on PB/N-doped CNTs was applied to in situ detect UA in human serum, delivering a wide dynamic detection range (0.001-1 mM) and a low detection limit (0.26 µM). This work provides a high-performance UA sensor while shedding a scientific light on using atomic matching catalysis to fabricate highly sensitive and selective biomimetic sensors.

Center-iodized graphene as an advanced anode material to significantly boost the performance of lithium-ion batteries.

Iodine edge-doped graphene can improve the capacity and stability of lithium-ion batteries (LIBs). Our theoretical calculations indicate that center-iodization can further significantly enhance the anode catalytic process. To experimentally prove the theoretical prediction, iodine-doped graphene materials were prepared by one-pot hydrothermal and ball-milling approaches to realize different doping-sites. Results show that the center-iodinated graphene (CIG) anode exhibits a remarkably high reversible capacity (1121 mA h g-1 after 180 cycles at 0.5 A g-1), long-cycle life (0.01% decay per cycle over 300 cycles at 1 A g-1) and high-rate capacity (374 mA h g-1 after 800 cycles at 8 A g-1), which greatly improves the performance of the edge-iodinated graphene anode and these results are in good agreement with the theoretical analysis. More importantly, the CIG anode also delivers a high-rate capacity and excellent cycling stability (279 mA h g-1 after 500 cycles at 10 A g-1) in full-cells. Both the theoretical analysis and experimental investigation reveal the enhancement mechanism, in which the center-iodization increases the surface charge for fast electron transfer rate, improves the conductivity for charge transport and rationalizes the pore structure for enhanced mass transport and ion insertion/desertion, thus resulting in a high rate capacity and long cycle life. This work not only discloses the critical role of catalytic sites including both amounts and site positions but also offers great potential for high-power rechargeable LIB applications.

F-Doping effects on carbon-coated Li3V2(PO4)3 as a cathode for high performance lithium rechargeable batteries: combined experimental and DFT studies.

F-Doping effects on polyaniline-derived carbon coated Li3V2(PO4)3 (Li3V2(PO4)3-xFx@C) as a cathode for high performance Li rechargeable batteries are systematically investigated with a combined experimental and DFT theoretical calculation approach. The results clearly indicate that the doping amount has a significant impact on the rate capability and long cycle life. The optimal material (Li3V2(PO4)2.88F0.12@C) delivers 123.16 mA h g-1@2C, which is close to the theoretical value (133 mA h g-1), while showing a greatly improved cycle stability. Rietveld refinements show that the F- doping does not obey Vegard's Law, which may be attributed to the generated lower valence of V ions. AC impedance spectroscopy shows that the F-doping can achieve faster interfacial charge transfer for higher reaction reversibility. DFT calculations confirm that the lower V2+ (t2g↑)3 does exist in Li3V2(PO4)2.88F0.12, and the mean nearest neighbor Li-O bond length also increases for faster electrochemical kinetics, and further reveal that there is a tendency for a transition from the insulator to the n-type semiconductor due to the F dopant. The combined experimental and calculated results suggest that F-doping indeed greatly facilitates the charge transfer rate of the Li+ insertion/de-insertion process for better reversibility and enhances the Li+ diffusion rate to access the reaction sites, thus resulting in high rate capacity and cycling stability. This work not only offers a facile and effective approach to synthesize high performance Li-ion battery material for very promising practical applications, but also discloses scientific insights on element coating and doping to guide the electrode material design for fast electrode kinetics in energy storage devices.

Borate-ion intercalated NiFe layered double hydroxide to simultaneously boost mass transport and charge transfer for catalysis of water oxidation.

Borate ion-intercalated NiFe layered double hydroxide (NiFe LDH) is synthesized as a highly active electrocatalyst toward oxygen evolution reaction (OER) for the first time. With the intercalation of borate ions, the interlayer spacing and specific surface area of the NiFe LDH are increased, meanwhile the pore size distribution shifts to a larger pore size range. The borate ion-intercalated catalyst prepared at 20% of Fe content in presence of 0.05 M sodium borate additive exhibits the highest OER electrocatalytic activity, which shows a low onset overpotential of 270 mV and a Tafel slope of 42 mV dec-1. The high catalytic activity of intercalated OER catalyst can be attributed to the enhanced mass transport and charge transfer as well as the increased specific surface area due to the borate ion intercalation. In addition, the intercalated borate ions act as a proton-accepting agent help to promote OO bond formation during OER. This work would open up a novel strategy for the synthesis of ion-intercalated layered materials for high-performance water splitting applications.