Potassium‐ion batteries (PIBs), using carbon materials as the anode, are regarded as a promising alternative to lithium‐ion batteries owing to the feasible formation of stage‐1 potassium intercalation compounds (KC8). However, due to the large radius of the potassium ion, graphite‐based electrodes still suffer poor rate capability and insufficient cycling life. In this work, a hierarchically nitrogen‐doped porous carbon (NPC) is reported for the first time. The NPC electrode delivers a high reversible capacity of 384.2 mAh g−1 after 500 cycles at a current density of 0.1 A g−1 and an outstanding rate capability of 185 mAh g−1 at 10.0 A g−1, which surpasses most of the reported carbonaceous electrodes in PIBs. The excellent performance can be ascribed to the surface‐driven behavior dominated K‐storage mechanism, which is verified by quantitative kinetics analysis. Theoretical simulation results further illuminate the enhanced K affinity in N‐doped active sites, which accounts for the superior rate performance of the NPC electrode. In addition, galvanostatic intermittent titration technique measurements further quantify the diffusion coefficient of K ions. Considering the superior electrochemical performance of the electrode and comprehensive investigation of the K storage mechanism, this work can provide fundamental references for the subsequent research of potassium‐ion batteries.

[1] This paper introduced the calibration of the CE-318 sunphotometer of the China Aerosol Remote Sensing Network (CARSNET) and the validation of aerosol optical depth (AOD) by AOD module of ASTPWin software compared with the simultaneous measurements of the Aerosol Robotic Network (AERONET)/Photométrie pour le Traitement Opérationnel de Normalization Satellitaire (PHOTONS) and PREDE skyradiometer. The results show that the CARSNET AOD measurements have the same accuracy as the AERONET/PHOTONS. On the basis of a comparison between CARSNET and AERONET, the AODs from CARSNET at 1020, 870, 670, and 440 nm are about 0.03, 0.01, 0.01, and 0.01 larger than those from AERONET, respectively. The aerosol optical properties over Beijing acquired through the CE-318 sunphotometers of one AERONET/PHOTONS site and two CARSNET sites were analyzed on the basis of 4-year measurements. It was obvious that the AOD of the Shangdianzi site (rural site) was lower than that of the two urban sites (the Institute of Atmospheric Physics (IAP) site (north urban site) and the Beijing Meteorological Observatory (BJO) site (south urban site)). The AOD of BJO was about 0.05, 0.04, 0.05, and 0.06 larger than that of IAP at 1020, 870, 670, and 440 nm, respectively, indicating that there is more local pollution in the south part of Beijing. The highest AOD was found in summer because of the stagnation planetary boundary layer and transport of pollutants from large pollution centers south of Beijing. The high temperature and relative humidity in summer also favor the production of aerosol precursor and the hygroscopic growth of the existing particles locally, which results in high AOD. In contrast, the lowest AOD at the two urban sites and one rural site in Beijing occurred in winter as the frequent cold air masses help pollutants diffuse easily.

Potassium-ion batteries (PIBs) have been regarded as promising alternatives to lithium-ion batteries in large-scale energy storage systems owing to the high abundance and low cost of potassium. However, the large...

Conversion-alloying type anode materials like metal sulfides draw great attention due to their considerable theoretical capacity for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). However, poor conductivity, severe volume change, and harmful aggregation of the material during charge/discharge lead to unsatisfying electrochemical performance. Herein, a facile and green strategy for yolk-shell structure based on the principle of metal evaporation is proposed. SnS 2 nanoparticle is encapsulated in nitrogen-doped hollow carbon nanobox (SnS 2 @C). The carbon nanoboxes accommodate the volume change and aggregation of SnS 2 during cycling, and form 3D continuous conductive carbon matrix by close contact. The well-designed structure benefits greatly in conductivity and structural stability of the material. As expected, SnS 2 @C exhibits considerable capacity, superior cycling stability, and excellent rate capability in both SIBs and PIBs. Additionally, in situ Raman technology is unprecedentedly conducted to investigate the phase evolution of polysulfides. This work provides an avenue for facilely constructing stable and high-capacity metal dichalcogenide based anodes materials with optimized structure engineering. The proposed in-depth electrochemical measurements coupled with in situ and ex situ characterizations will provide fundamental understandings for the storage mechanism of metal dichalcogenides.

The electrode–electrolyte interface stability is a critical factor influencing cycle performance of All-solid-state lithium batteries (ASSLBs). Here, we propose a LiF- and Li3N-enriched artificial solid state electrolyte interphase (SEI) protective layer on metallic lithium (Li). The SEI layer can stabilize metallic Li anode and improve the interface compatibility at the Li anode side in ASSLBs. We also developed a Li1.5Al0.5Ge1.5(PO4)3–poly­(ethylene oxide) (LAGP-PEO) concrete structured composite solid electrolyte. The symmetric Li/LAGP-PEO/Li cells with SEI-protected Li anodes have been stably cycled with small polarization at a current density of 0.05 mA cm–2 at 50 °C for nearly 400 h. ASSLB-based on SEI-protected Li anode, LAGP-PEO electrolyte, and LiFePO4 (LFP) cathode exhibits excellent cyclic stability with an initial discharge capacity of 147.2 mA h g–1 and a retention of 96% after 200 cycles.

Potassium‐ (PIBs) and sodium‐ion batteries (SIBs) are emerging as promising alternatives to lithium‐ion batteries owing to the low cost and abundance of K and Na resources. However, the large radius of K+ and Na+ lead to sluggish kinetics and relatively large volume variations. Herein, a surface‐confined strategy is developed to restrain SnS2 in self‐generated hierarchically porous carbon networks with an in situ reduced graphene oxide (rGO) shell (SnS2@C@rGO). The as‐prepared SnS2@C@rGO electrode delivers high reversible capacity (721.9 mAh g−1 at 0.05 A g−1) and superior rate capability (397.4 mAh g−1 at 2.0 A g−1) as the anode material of SIB. Furthermore, a reversible capacity of 499.4 mAh g−1 (0.05 A g−1) and a cycling stability with 298.1 mAh g−1 after 500 cycles at a current density of 0.5 A g−1 were achieved in PIBs, surpassing most of the reported non‐carbonaceous anode materials. Additionally, the electrochemical reactions between SnS2 and K+ were investigated and elucidated.

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