Potassium‐ion batteries (PIBs) are promising energy storage systems because of the abundance and low cost of potassium. The formidable challenge is to develop suitable electrode materials and electrolytes for accommodating the relatively large size and high activity of potassium. Herein, Bi‐based materials are reported as novel anodes for PIBs. Nanostructural design and proper selection of the electrolyte salt have been used to achieve excellent cycling performance. It is found that the potassiation of Bi undergoes a solid‐solution reaction, followed by two typical two‐phase reactions, corresponding to Bi ↔ Bi(K) and Bi(K) ↔ K5Bi4 ↔ K3Bi, respectively. By choosing potassium bis(fluorosulfonyl)imide (KFSI) to replace potassium hexafluorophosphate (KPF6) in carbonate electrolyte, a more stable solid electrolyte interphase layer is achieved and results in notably enhanced electrochemical performance. More importantly, the KFSI salt is very versatile and can significantly promote the electrochemical performance of other alloy‐based anode materials, such as Sn and Sb.

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Potassium-ion batteries (PIBs) are a promising alternative to lithium-ion batteries because potassium is an abundant natural resource. To date, PIBs are in the early stages of exploration and only a few anode materials have been investigated. This study reports a cobalt sulfide and graphene (CoS@G) composite as anode electrode for PIBs for the first time. The composite features interconnect quantum dots of CoS nanoclusters uniformly anchored on graphene nanosheets. The coexistence of CoS quantum dot nanoclusters and graphene nanosheets endows the composite with large surface area, highly conductive network, robust structural stability, and excellent electrochemical energy storage performance. An unprecedented capacity of 310.8 mA h g −1 at 500 mA g −1 is obtained after 100 cycles, with a rate capability better than an equivalent sodium-ion batteries (SIBs). This work provides the evidence that PIBs can be a promising alternative to SIBs, especially at high charge-discharge rates. The development of the CoS@G anode material also provides the basis of expanding the library of suitable anode materials for PIBs.

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A new reversible and high-performance potassium-selenium (K-Se) battery, using confined selenium/ carbonized-polyacrylonitrile (PAN) composite (c-PAN-Se) as cathode and metallic potassium as anode, is reported in this work. The PAN-derived carbon matrix could effectively confine the small Se molecules and provide a sufficient buffer for the volume changes. The reversible formation of small-molecule trigonal Se (Se1, P3121) phase could essentially inhibit the formation of polyselenides and account for outstanding electrochemical performance. The carbonate-based electrolyte further synergistically diminishes the shuttle effect by inhibiting the formation of polyselenides in the meantime. The as-prepared K-Se battery shows a reversible capacity of 1904 mAh cm¿3after 100 cycles at 0.2 C and rate retention of 89% from 0.1 to 2 C. In addition, the charge-discharge mechanism is also investigated via the combination of in-situ and ex-situ synchrotron X-ray diffraction (XRD), and Raman spectroscopy analysis. The results reveal that the introduction of K+ions leads to the cleavage of C-Se bonds, the rearrangement of selenium atoms, and the final formation of the main product K2Se. Moreover, the reversible formation of trigonal Se (Se1, P3121) phase was detected in the reaction with K+. These findings not only can advance our understanding of this family of batteries, but also provide insight into chemically-bonded selenium composite electrodes, which

grids. Current growth rates in lithiumion battery (LIB) manufacturing are not sustainable given our limited lithium resources. In this context, alternative battery systems with low cost are sought, with sodium-and potassium-ion batteries (SIBs and PIBs, respectively) regarded as suitable replacements due to the high natural abundance of sodium and potassium and their similar working mechanism to LIBs. [1] Of these, PIBs are more promising due to the closeness of the K + /K redox potential (−2.9 V vs H + /H 2 O) to that of Li + /Li (−3.0 V vs H + /H 2 O), as compared to Na + /Na (−2.7 V vs H + /H 2 O), and the consequential ease of reversible K + intercalation into the most common LIB negative electrode, graphite. [2][3][4] The slow kinetics of the reversible insertion of K + in electrode materials as a result of its relatively large ionic radius of 1.38 Å is a major issue for the realization of high-performance PIBs. [5][6][7] For PIB technology to be successful, scientists need to find stable electrode materials capable of reversibly hosting K + relatively quickly. Transition metal layered oxides possess a 2D structure that can accommodate large ions and are attracting interest as potential PIB electrode materials. [8][9][10][11][12][13][14] Among these, manganese layered oxides are particularly promising due to the high natural abundance and nontoxicity of manganese. A range of layered K x MnO 2 structure types can be prepared [15,16] including Potassium-ion batteries (PIBs) are an emerging, affordable, and environmentally friendly alternative to lithium-ion batteries, with their further development driven by the need for suitably performing electrode materials capable of reversibly accommodating the relatively large K + . Layer-structured manganese oxides are attractive as electrodes for PIBs, but suffer from structural instability and sluggish kinetics of K + insertion/extraction, leading to poor rate capability. Herein, cobalt is successfully introduced at the manganese site in the K x MnO 2 layered oxide electrode material and it is shown that with only 5% Co, the reversible capacity increases by 30% at 22 mA g -1 and by 92% at 440 mA g -1 . In operando synchrotron X-ray diffraction reveals that Co suppresses Jahn-Teller distortion, leading to more isotropic migration pathways for K + in the interlayer, thus enhancing the ionic diffusion and consequently, rate capability. The detailed analysis reveals that additional phase transitions and larger volume change occur in the Co-doped material as a result of layer gliding, with these associated with faster capacity decay, despite the overall capacity remaining higher than the pristine material, even after 500 cycles. These results assert the importance of understanding the detailed structural evolution that underpins performance that will inform the strategic design of electrode materials for high-performance PIBs.

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Lung cancer is one of the leading causes of death worldwide. There are three major types of lung cancers, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC) and carcinoid. NSCLC is further classified into lung adenocarcinoma (LADC), squamous cell lung cancer (SQCLC) as well as large cell lung cancer. Many previous studies demonstrated that DNA methylation has emerged as potential lung cancer-specific biomarkers. However, whether there exists a set of DNA methylation markers simultaneously distinguishing such three types of lung cancers remains elusive. In the present study, ROC (Receiving Operating Curve), RFs (Random Forests) and mRMR (Maximum Relevancy and Minimum Redundancy) were proposed to capture the unbiased, informative as well as compact molecular signatures followed by machine learning methods to classify LADC, SQCLC and SCLC. As a result, a panel of 16 DNA methylation markers exhibits an ideal classification power with an accuracy of 86.54%, 84.6% and a recall 84.37%, 85.5% in the leave-one-out cross-validation (LOOCV) and independent data set test experiments, respectively. Besides, comparison results indicate that ensemble-based feature selection methods outperform individual ones when combined with the incremental feature selection (IFS) strategy in terms of the informative and compact property of features. Taken together, results obtained suggest the effectiveness of the ensemble-based feature selection approach and the possible existence of a common panel of DNA methylation markers among such three types of lung cancer tissue, which would facilitate clinical diagnosis and treatment.