Jiajun Wan,Qian Zhang,Xu Jia,Pengfei Zhang,Yuanze Yu,Jiyang Tian,Jie Liu
Aqueous Zn-ion batteries (AZIBs) recently have attracted broad attention. To achieve high energy density of AZIBs, constructing high-loading cathodes is the prerequisite. However, the cycling stability of high-loading cathodes still faces great challenges. Herein, a comprehensive strategy is proposed to improve the structural stability of the cathode material and mechanical stability of the high-loading cathode. The BiOBr@BiOIO 3 heterostructure are successfully constructed via sharing the interfacial oxygen atoms, in which the interfacial effect can effectively enhance the reaction dynamics and structural stability. Meanwhile, a biomimetic binder is skillfully designed via in situ dual cross-linking between guar gum and cation ions to achieve the application of water-based and sustainable polymer binder in AZIBs. Density functional theory calculations demonstrate the guar gum possesses strong affinity toward BiOBr@BiOIO 3 to firmly adhere the active materials. Quantitative nanomechanic technology visually demonstrates the robust mechanical properties of the as-obtained BiOBr@BiOIO 3 cathode. As a result, when the active material loading increases to as high as 100.71 mg cm −2 , an ultrahigh areal capacity of 20.02 mAh cm −2 can be achieved. Specially, a quasi-Ah-level (0.244 Ah) pouch-type cell with a loading of 1.17 g can be constructed, showing the practical application potential.
Two-dimensional (2D) materials exhibit a strong propensity for exciton generation upon photoexcitation compared to bulk counterparts. However, as exciton relaxation processes, intersystem crossing (ISC) and exciton dissociation always compete in the carrier dynamics. This study presents a strategy to decouple exciton dissociation and ISC by introducing a nitrogen-doped biochar (NBC) as the ISC center to modify Z-scheme heterojunction (BiOBr/BiOIO 3 , BB). NBC-BB achieved a 1.75 times interfacial driving force compared to BB and suppressed the exciton binding energy (E b ) from 107 meV to 85 meV. Moreover, due to the spontaneous incorporation of Br into NBC during the preparation process, the singlet and triplet energy level difference (ΔE ST ) was shortened by 0.079 eV to intensify ISC on NBC. The constructive collaboration of exciton dissociation and ISC guaranteed the generation of reactive oxygen species (ROS) with strong redox potential and selectivity, achieving efficient removal of refractory organic pollutants under visible light. The bolstered oxygen adsorption indicated effective oxygen activation capability of NBC-BB, leading to a 1.4-fold and 3.1-fold increase in the generation efficiency of 1 O 2 and •O 2 − , respectively. This study also presented experiments on various influencing factors, cyclic stability, and a feasible continue-flow system, showcasing the stability and potential for the practical application.
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