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Onion-like carbon (OLC) is one kind of a quasi-nanosphere with a concentric graphite shell structure and abundant mesopores, which is appropriate for a high rate of charging/discharging and long-lifespan cycling. However, the moderate specific surface area seriously impeded its capacitance performance in comparison with activated carbon and porous carbon. Herein, we have unlocked the Zn ion storage performance of OLC material through introducing N and P dopants. Benefitting from the fabricated N,P-OLC with a fully accessible external surface area for ion adsorption, high proportion of mesopores for fast ion migration, and synergistic effect of N and P co-doping in a carbon matrix favoring chemical adsorption of Zn 2+ ions, when applied as a cathode electrode for Zn ion hybrid supercapacitors (ZHSCs), such a device can deliver a high specific capacitance of 420.3 F g −1 (184.5 mA h g −1 ) at 0.5 A g −1 , an outstanding capacitance retention capability of 262.7 F g −1 even at 20 A g −1 (∼63% capacitance retention), a high energy density of 149.5 W h kg −1 , and a high power density of 26.7 kW kg −1 . Furthermore, this N,P-OLC material can in situ tightly integrate with a carbon cloth (CC) or carbon fiber to construct a freestanding and flexible electrode. The fabricated Zn//N,P-OLC@CC device achieved a high energy density of 85.3 mW h cm −2 , a high power density of 24.3 W cm −2 , and a long-term cycling lifespan (77.8% after 50 000 cycles). At last, the assembled quasi-solid-state fiber-shaped ZHSCs also present excellent flexibility and practicality. Our study exhibits that OLC can act as a promising carbon electrode for ZHSCs.

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Due to the large height and span of indoor spaces, efficient indoor ventilation performance may be difficult to achieve using the side air supply for large halls, to control the indoor air pollutants or reduce the infection risk, such as the transmission of COVID-19 within the breathing zone of occupants. An efficient Ventilation Mode with Deflector and Slot air outlets (VMDS) was developed by this study. The use of a deflector with slot air outlets was introduced by utilizing jet collision and adhesion effect to accentuate the ventilation performance of the side air supply for the large space. The numerical simulation model used in this study was validated experimentally. The VMDS was compared with three other side air supply modes used in large spaces, and the results were evaluated comprehensively. The results show that VMDS is effective in reducing indoor air pollutant concentrations and transmission of infectious diseases in large spaces while satisfying the energy efficiency and thermal comfort requirements. Compared with the common side-supply and side-return ventilation modes, VMDS can reduce indoor air pollutant concentration by nearly 40%, reduce the transmission risk of infectious disease to less than 1% at a low air change rate and increase the ventilation efficiency from about 0.85 to about 1.2. In addition, VMDS can theoretically reduce ventilation energy consumption by about 85%.

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