COVID-19 causes a global epidemic infection, which is the most severe infection disaster in human history. In the absence of particular medication and vaccines, tracing and isolating the source of infection is the best option to slow the spread of the virus and reduce infection and death rates among the population. There are three main obstacles in the process of tracing the infection: 1) Patient's electronic health record is stored in a traditional centralized database that could be stolen and tampered with the infection data, 2) The confidential personal identity of the infected user may be revealed to a third party or organization, 3) Existing infection tracing systems [1] [2] do not trace infections from multiple dimensions. Either the system is location-based or individual-based tracing. In this work, we propose a global COVID-19 information sharing system that utilizes the Blockchain, Smart Contract, and Bluetooth technologies. The proposed system unifies location-based and Bluetoothbased contact tracing services into the Blockchain platform, where the automatically executed smart contracts are deployed so that users can get consistent and non-tamperable virus trails. The anonymous functionality provided by the Blockchain and Bluetooth technology protects the user's identity privacy. With our proposed analysis formula for estimating the probability of infection, users can take measures to protect themselves in advance. We also implement a prototype system to demonstrate the feasibility and effectiveness of our approach.

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Transitional metal chalcogenide (TMC) is considered as one promising high‐capacity electrode material for asymmetric supercapacitors. More evidence indicates that TMCs have the same charge storage mechanism as hydroxides, but the reason why TMC electrode materials always provide higher capacity is rare to insight. In this work, a NixCoyMnzS/Ni(SeO3) (NCMS/NSeO) heterostructure is prepared on Ni‐plated carbon cloth, validating that both NCMS and NSeO can be transformed into hydroxides in electrochemical process as accompanying with the formation of SeO32‐ and SOx2− in confined spaces of NCMS/NSeO/Ni sandwich structure. Based on density functional theory calculation and experimental results, a novel space‐confined acidic radical adsorption capacity‐activation mechanism is proposed for the first time, which can nicely explain the capacity enhancement of NCMS/NSeO electrode materials. Thanks to the unique capacity enhancement mechanism and stable NCMS/NSeO/Ni sandwich structure, the optimized electrodes exhibit a high capacity of 536 mAh g−1 at 1 A g−1 and the impressive rate capability of 140.5 mAh g−1 at the amazing current density of 200 A g−1. The assembled asymmetric supercapacitor achieves an ultrahigh energy density of 141 Wh Kg−1 and an impressive high‐rate capability and cyclability combination with 124% capacitance retention after 10 000 cycles at a large current density of 50 A g−1.

The central goal of high-performance potassium ion storage is to control the function of the anode material via rational structural design. Herein, N-and S-doped hollow carbon spheres with outer-short-range-order and inner-disorder structures are constructed to achieve highly efficient and ultra-stable potassium ion storage using a low-temperature molten salt system. The ultrathin carbon walls and uniform mesoporous as well as unique heterostructure synergistically realize significant potassium storage performance via facilitating rapid diffusion of potassium ions and alleviating substantial volume expansion. Furthermore, as the anode of a potassium ion battery, the as-prepared MSTC electrode demonstrates a state-of-the-art cycling capability of 221.3 mAh g −1 at 1 A g −1 after 20,000 cycles. The assembled potassium ion hybrid capacitor device demonstrates a high energy of 157 Wh kg −1 at 956 W kg −1 and excellent reversibility at a current density of 5.0 A g −1 after 20,000 cycles with 82.7% capacity retention. Accordingly, our work provides new ideas for designing advanced carbon anode materials and understanding the charge storage mechanism in potassium ion battery, as well as constructing high energy-power density potassium-ion hybrid capacitors (PIHCs).