Manganese-based material is a prospective cathode material for aqueous zinc ion batteries (ZIBs) by virtue of its high theoretical capacity, high operating voltage, and low price. However, the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be undesirable. In this work, heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO₂ (δa-MnO₂) by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion batteries. Meanwhile, the heterointerface between the disordered amorphous and the crystalline MnO₂ of δa-MnO₂ is decisive for the formation of oxygen defects. And the experimental results indicate that the manganese dissolution of δa-MnO₂ is considerably inhibited during the charge/discharge cycle. Theoretical analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding state of the electrode material, thereby promoting electron transport kinetics as well as inhibiting Mn dissolution. Consequently, the capacity of δa-MnO₂ does not degrade after 100 cycles at a current density of 0.5 A g⁻¹ and also 91% capacity retention after 500 cycles at 1 A g⁻¹. This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.

The fast and high response detection of neurotoxic H₂S is of great importance for the environment. In this paper, directly electrospinning technology on the ceramic tube is developed to improve the response of H₂S detector based on superlong SnO₂ fibers. The submillimeter continuous fibers are deposited directly on ceramic tubes by in-situ electrospinning method and can keep morphology of fibers during calcination. By employing this technology, CuO-doped SnO₂ fiber H₂S detectors are fabricated, and 10% atom CuO-doped SnO₂ H₂S detector shows the highest response of 40 toward 1 ​ppm ​H₂S at 150 ​℃ while the response is only 3.6 for the H₂S detector prepared in traditional route. In addition, the in-situ electrospinning H₂S detectors show faster response and recovery compared to the H₂S detectors fabricated by the conventional way. The high and fast response of H₂S detectors based on in-situ electrospinning can be ascribed to the continuous fiber structure and CuO modification. The present in-situ electrospinning technology may provide a new strategy for the development of other gas-detectors and bio-detectors with fast and high response.

Potassium-based energy storage devices (PEDS) are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte. although carbon materials show great potential for potassium-ion storage, poor rate performance, and unsatisfactory cycle lifespan in existing carbon-based PIBs anode, it also cannot match the dynamics and stability of the capacitor cathode. Nitrogen doping has been proven to be a effective modification strategy to improve the electrochemical performance of carbon materials. Hence, we prepare carbon nanofibers and g-C₃N₄ composites with high nitrogen contents (19.78 at%); moreover, the sum of pyrrolic N and pyridinic N is up to 59.51%. It achieves high discharge capacity (391 mAh g⁻¹ at 0.05 A g⁻¹), rate capacity (141 mAh g⁻¹ at 2 A g⁻¹), and long cycling performance (201 mAh g⁻¹ at 1 A g⁻¹ over 3000 cycles) when as an anode for PIBs. Furthermore, it can deliver promising discharge capacity of 132 mAh g⁻¹ at 0 °C. Moreover, as battery anode for potassium-ion hybrid capacitors (PIHC) device with an active carbon cathode, it delivers energy/power density (62 and 2102 W kg⁻¹) as well as high reversible capacity (106 mAh g⁻¹ at 1 A g⁻¹).