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Carbonaceous materials are regarded as prospective anode candidates of potassium‐ion batteries. However, the rate capability and cycling stability of classic carbon materials are still far from satisfactory. Herein, we exploit a facile and low‐cost strategy to enable the precise synthesis of sulfur/nitrogen co‐doped in‐plane porous carbon nanosheets with fishnet‐shaped microstructure (SN‐CNSs). The well‐designed in‐plane porous structure and the interconnected carbon flake network can accelerate the diffusion of potassium ions, alleviate volume expansion, and provide sufficient active sites. As a result, the SN‐CNSs deliver an impressively reversible capacity of 248 mAh g−1 at a current density of 1 A g−1 after 4500 cycles, and an excellent rate capacity of 137.3 mAh g−1 after 4000 cycles under 5 A g−1. Density functional theory (DFT) calculations further verify the advantage of S/N co‐doping in the adsorption/diffusion of K‐ion in SN‐CNSs materials. Such an excellent performance shows that SN‐CNSs possess a great potential to be a superior anode of potassium‐ion batteries. [ABSTRACT FROM AUTHOR]

Sodium ion batteries have been suffering low reversible capacity, poor rate, and less cycling reliability upon sodiation/desodiation. To address those formidable issues, electrospinning combined with hard template route is adopted here to collect loofah‐like nitrogen‐doped hollow carbon nanofibers (NHCNFs) derived from sustainable and low‐cost resources, that is, renewable acrylic yarn. NHCNFs render a remarkable reversible capacity of 143 mAh g−1 for 5000 cycles at a current density of 10 A g−1 at ambient temperature. More importantly, NHCNFs possesses an impressive capability in tackling the elevated temperature environment, affording an admirable reversible capacity of 156 mAh g−1 at a high rate of 15 A g−1 even after 10 000 cycles under 50 °C. These superior performances could be attributed to the combination of the following factors: delicately designed microstructure with hollow bead‐like channels, pseudocapacitive behavior and accelerated kinetics. Such an excellent attribute enables loofah‐like NHCNFs to be a promising low‐cost and environment‐friendly anode for sodium ion rechargeable batteries. [ABSTRACT FROM AUTHOR]

Cover Feature: Sulfur/Nitrogen Co-Doped In-Plane Porous Carbon Nanosheets as Superior Anode of Potassium-Ion Batteries (Batteries & Supercaps 5/2022) Carbon nanosheets, DFT calculations, low temperature graphitization, porous structure, potassium-ion batteries anode Keywords: carbon nanosheets; DFT calculations; low temperature graphitization; porous structure; potassium-ion batteries anode EN carbon nanosheets DFT calculations low temperature graphitization porous structure potassium-ion batteries anode 1 1 1 05/10/22 20220501 NES 220501 B The Cover Feature b shows porous carbon nanosheets with fishnet-like microstructures, featuring excellent potassium-ion storage capacity as anodes for potassium-ion batteries, possessing great potential for powering the future city. [Extracted from the article]

Potassium-ion batteries are of utmost interest to researchers as emerging energy storage device due to abundant resource and high safety. However, they've been suffering low reversible capacity, poor rate and unreliable cycling stability during potassiation/depotassiation because of larger size of potassium ion. Here, for the first time, a sustainable and low-cost resource, i.e. , renewable acrylic yarn, as raw materials were used to prepare N -doped mesoporous carbon nanofibers (NMCNFs) by using facile electrospinning then followed with "high temperature self-fluid technology". The consequent internal cross-linked multiple pores and high nitrogen-doping emerged in elaborately carved N -doped mesoporous carbon nanofibers, providing sufficient active-sites and shortened ion diffusion paths. The resultant NMCNFs delivered an impressively reversible capacity of 351.1 mAh g−1 after 500 cycles at a current density of 200 mA g−1, outstanding rate performance of 134 mAh g−1 at 10 A g−1. Even at a high rate of 5 A g−1, reversible capacity of 122.3 mAh g−1 has been enduringly retained after 20,000 cycles. The result of the density functional theory (DFT) calculations revealed the pyridinic/pyrrolic N -doping could effectively enhance the adsorption of K+ to the NMCNFs electrode, which boosted the K-ion storage capability of NMCNFs. Such excellent attributes above make NMCNFs to be a promising low-cost and environment-friendly anode for next-generation potassium-ion rechargeable batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Self-assembly by electrostatic interaction between silane and MOF ligand. • The activation mechanism of electrochemical inert metal Co in SiO x materials was investigated. • The catalytic action of atomic Co site activates Si O bond and Li O bond to increase SiO x capacity and coulomb efficiency. • High mechanical strength and high conductivity Co nanoparticles enhance the conductivity and cycling stability of SiO x. The ultra-high theoretical capacity of silicon-based (Si) materials makes them promising anode materials for high energy density lithium-ion batteries. Unfortunately, the dramatic volume change (∼300%) and low electrical conductivity of silicon have severely hindered the commercial use of silicon anodes. Silicon suboxide (SiO x) is one of the ideal candidates for high energy density batteries due to its reduced swelling and lower cost as compared to silicon. However, it remains a huge challenge to address the low conductivity, low (initial) coulombic efficiency and apparent volume effects of SiO x. In this paper, SiO x /Co@C composite anode materials loaded with metal Co nanoparticles were uniformly and efficiently prepared by using 3-aminopropyl triethoxysilane (APTES) as silicon source and Co-MOF as Co source via molecular self-assembly strategy. The experimental results and density functional theory (DFT) calculation showed that the catalytic action of embedded Co nanoparticles had activated the silico-oxygen bond of SiO x and the irreversible product Li 2 O, thereby improving the initial coulombic efficiency (ICE) and enhancing the reversible capacity. At the same time, the metal Co with mechanical rigidity and electrical conductivity alleviated the volume fluctuation during alloying and improved the charge transfer capacity and ion transport rate of the composite. When compared with SiO x @C anodes, SiO x /Co@C-600 composites showed higher initial CE, superior cyclic stability and good rate performance. In particular, the successful matching of the anode with the lithium iron phosphate (LFP) cathode in full cell systems validated the possibility of its practical application. This work provides important insights into the application of Si-based materials in lithium-ion battery electrode materials and the development of high energy density batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • A self-sacrificial protocol was proposed for controllable synthesis of ZnTiO 3 /TiO 2 /C composites. • The enriched oxygen vacancies facilitate the boosted lithium-ion diffusion. • Both experimental and theoretical studies verify the superior electrochemical performance. With the growing demand for better electrochemical properties of lithium-ion batteries (LIBs), the design and development of alternatives for commercial electrodes has become an emerging field in energy research arena. In this paper, we reported an effective strategy using a bimetallic zeolite imidazole framework ZIF-8 (Zn, Ti) as the sacrificial template for synthesis of the oxygen-deficient ZnTiO 3 /TiO 2 /C (ZTC) composite as an advanced anode material for LIBs. Benefitting from the nanostructure retained from the MOF precursor, the unique electronic property provided by the abundant oxygen vacancies, synergistic effect of the multiphase composition, the ZTC composite prepared by calcination at 700 °C (ZTC-700) delivers not only a remarkable reversible capacity of 357.6 mA h g−1 at a current density of 300 mA g−1 after 400 cycles, but also an outstanding rate performance with a reversible capacity of 155 mA h g−1 at an elevated current density of 500 mA g−1 for 1500 cycles. To further investigate the lithium storage mechanism of the composites, density functional theory (DFT) calculation is employed to identify enhanced electrochemical performance of ZTC composites compared with pure rutile TiO 2 due to the boosted diffusion kinetics. This study provids insights for the morphology and micro structure control from atomic level by MOF-templated method and the utilization of different components for better synergy. [ABSTRACT FROM AUTHOR]

Traditional manganese trioxide (Mn 2 O 3) as anode materials can be applied to lithium-ion batteries (LIBs), where it possesses excellent electrochemical performance. However, the inherent disadvantages of volume change and poor cycling stability during charge/discharge process hinder the application of transition metal oxide (TMO) in LIBs. Herein, we propose a method to derive Mn 2 O 3 from metal-organic framework in order to mitigate volume change and enhance cycling stability, by virtue of the introduction of oxygen vacancies (O V) and stable template-derived structure for boosted lithium storage properties. Interestingly, M-BTEC (pyromellitic acid based MOF) -derived Mn 2 O 3 represented higher specific capacity of 1227.1 mAh g−1 until 200 cycles with the current density of 0.1 A g−1 while M-IN (isonicotinic acid based MOF) shows 723.4 mAh g−1 with exceptional cycling stability. [Display omitted] • Two different ligands were used to synthesized Mn 2 O 3 and both of which possess cyclic stability and unique structure. • Oxygen vacancies was conducive to boost lithium ion storage performance. • M-BTEC and M-IN displays excellent capacity of 1227.1 mAh g−1while M-IN shows 723.4 mAh g−1 (200 cycles at 0.1 A g−1) [ABSTRACT FROM AUTHOR]

Potassium-ion energy-storage devices have established themselves as the most important candidates for next-generation energy-storage devices in the coming future. Recently, inorganic electrode materials have riveted ever-increasing interest due to large theoretical capacity, rich sources, low price and environmental friendly advantages. However, the electrode materials of potassium-containing devices have been suffering low theoretical capacity, poor rate performance and short lifespan due to integration effects of seriously electrochemical pulverization and slow kinetics. In this timely review, we will focus on the latest progress of potassium ion energy storage devices based on beyond-carbon materials, referring to the synthesis of materials and the construction of microstructure, material component-oriented electrochemical performance, energy storage mechanism discussion, newfangled device assembly and key components. The key materials and novel theories are reviewed, and some personal viewpoints have been proposed, targeting providing some inductive opinions. Potassium-ion energy-storage devices have established themselves as one of the most important candidates for next-generation energy-storage devices in the coming future. In this timely review, we will focus on the latest progress of key materials and novel theories in potassium-containing devices. And some personal viewpoints have been proposed, targeting providing some inductive opinions. [Display omitted] • The beyond-carbon anode materials for potassium ion batteries were systematically analyzed and summarized. • Other components of potassium ion batteries, such as cathode, electrolyte and binder, were also studied. • The development bottleneck of potassium ion battery was analyzed and some countermeasures were put forward. • It provides comprehensive and reliable information and enlightening opinions for the researchers of new energy devices. [ABSTRACT FROM AUTHOR]