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[Display omitted] • A machine-learning model is constructed based on experimental data to predicate the gas-sensing performance of oxides. • Six important features are proposed as the descriptors for gas sensing of oxides. • The active sites on oxides for gas sensing are described as ionic oxygen loosely bonded to metal atoms. Machine learning, a new research paradigm, is promising for device design, material discovery, and theoretical exploration, overcoming the drawbacks of experimental approaches. In this study, we used machine learning to explore the gas-sensing reactions of metal oxides. The training data were experimental results. Three types of features — metal oxide and gas molecule properties and operating conditions — were extracted as inputs for the machine learning algorithms. The genetic algorithm-adjusted artificial neural network achieved the best performance, and the neural network test was performed using two new experimental datasets. Further, Shapley Additive exPlanations were employed to understand the findings and explore key descriptors for gas sensing. The feature importance was ranked, and the first six features were selected as key descriptors for gas sensing using metal oxides. Furthermore, theoretical investigations were conducted, and the correlations between features and outcomes were analyzed. We found that the active site for gas sensing on pristine metal oxides comprises ionic oxygen loosely bonded to the metal sites. This study provides an example of the use of machine learning for material discovery. We expect that this study will encourage more studies on machine learning for gas sensing. [ABSTRACT FROM AUTHOR]

To address the volume expansion as well as improve the cycling stability and specific capacity of metal selenides, hollow NiCoMnSe (NCMSe) sub-microspheres are synthesised. The as-obtained NCMSe electrodes exhibit superior performance in both LIBs and SIBs and may open up a novel avenue for the rational design of anode materials for both LIBs and SIBs. • A novel trimetallic selenide hollow sphere is prepared for LIB/SIB anodes. • The material exhibits synergistic effect and multielectron redox reactions. • The material shows excellent electrochemical performance. • The ex-situ XRD and XPS provide insight into Li+/Na+ storage mechanism. Highly conductive metal selenides have drawn increasing attention in the field of energy storage. Unfortunately, their application is severely limited by the inferior capacity contribution as well as unsatisfactory cycling stability. Here, we propose a simple and practical way to prepare hollow nickel–cobalt–manganese selenides (NCMSe) submicrospheres. The NCMSe submicrospheres exhibit rich redox reactions during the reaction process into which much more alkali metal ions can be inserted, leading to high reversible capacity and their hollow structure facilitates the contact between the active material and electrolyte to accelerate the redox kinetics. Benefiting from these features, the hollow NCMSe submicrospheres show superior Li–storage capacity (1600 mAh g−1 after 1000 cycles at 2 A g−1) and Na–storage capacity (695 mAh g−1 after 200 cycles at 0.1 A g−1). This work offers a novel insight to the remarkable electrochemical performance anode materials for both lithium and sodium ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plum blossom-like CoSe 2 /N-doped carbon nanotubes S host was synthesized. • DFT calculation confirms the catalytic performance of CoSe 2 for Li 2 S x conversion. • The plum blossom-like structure is beneficial to the diffusion of electron/Li+. • DFT calculation confirms the chemical adsorption of CoSe 2 to Li 2 S x. • The CoSe 2 /hNCTs/S cathode delivers satisfactory lithium storage performance. Lithium-sulfur batteries (LSBs) have attracted wide attention as one of the most potential secondary batteries in the next generation. However, the low sulfur utilization, serious "shuttle effect", and large volume expansion of the sulfur cathode restrict the performance of LSBs. Here, CoSe 2 decorated hollow N-doped carbon nanotubes (CoSe 2 /hNCTs) were synthesized firstly, and then the CoSe 2 /hNCTs were used as a sulfur host to prepare a multifunctional CoSe 2 /hNCTs/S cathode. DFT calculations confirm that the CoSe 2 not only efficiently adsorbs lithium polysulfides (LiPSs), but also exhibits good catalytic performance for the conversion of LiPSs. SEM and TEM images indicate that the CoSe 2 uniformly disperses on the surface of the polypyrrole nanotube-derived hNCTs, like plum blossoms. The hNCTs with a morphology of plum blossom branches provide a high conductive network and prohibit large volume expansion during the electrochemical process. And the plum petal-like CoSe 2 on the hNCTs surface acts as a catalyst and an efficient polysulfides trap. The CoSe 2 /hNCTs/S cathode delivers a satisfactory lithium storage performance, which presents reversible capacities of 1156 and 640 mA h g−1 at 0.5 and 5C, respectively. Simultaneously, the cathode demonstrates excellent cycle stability with a slow capacity decay rate of 0.069% per cycle in 1000 cycles at 1C rate. This work provides a new idea for constructing composites of transition metal selenides and carbon materials, promoting the practical applications of LSBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multi-functional electrocatalyst of CoOOH/hollow carbon sphere (PHCS) was synthesized. • DFT calculation confirms the catalytic performance of CoOOH for Li 2 S x conversion. • DFT calculation certificates the promotion of CoOOH on OER reaction kinetic. • The CoOOH-PHCS cathode delivers satisfactory lithium storage performance. • The CoOOH-PHCS demonstrates excellent OER and ORR activity in the alkaline electrolyte. Materials with excellent electrocatalytic properties play an important role in the field of electrochemistry. In this work, a multi-function electrocatalyst of cobalt oxyhydroxide decorating homogeneous porous hollow carbon sphere (CoOOH-PHCS) was designed and fabricated. The CoOOH-PHCS can not only be used as an electrocatalyst to inhibit the shuttle effect in Li-S batteries (LSBs), but also can effectively accelerate the reaction kinetics in oxygen reduction/evolution reactions (ORR/OER). Meanwhile, density functional theory (DFT) calculations were performed to investigate the electrocatalytic activity of the CoOOH-PHCS. Benefiting from the synergy effect of CoOOH and PHCS, the CoOOH-HPC/S electrode exhibits a low capacity decay of 0.04% per cycle in 450 cycles at 1C. Meanwhile, the CoOOH-PHCS demonstrates excellent OER and ORR activity in the alkaline electrolyte. This work explores and reveals the application potential of CoOOH in electrocatalytic field. [ABSTRACT FROM AUTHOR]