Lithium (Li) has garnered considerable attention as an alternative anodes of next‐generation high‐performance batteries owing to its prominent theoretical specific capacity. However, the commercialization of Li metal anodes (LMAs) is significantly compromised by non‐uniform Li deposition and inferior electrolyte–anode interfaces, particularly at high currents and capacities. Herein, a hierarchical three‐dimentional structure with CoSe₂‐nanoparticle‐anchored nitrogen‐doped carbon nanoflake arrays is developed on a carbon fiber cloth (CoSe₂–NC@CFC) to regulate the Li nucleation/plating process and stabilize the electrolyte–anode interface. Owing to the enhanced lithiophilicity endowed by CoSe₂–NC, in situ‐formed Li₂Se and Co nanoparticles during initial Li nucleation, and large void space, CoSe₂–NC@CFC can induce homogeneous Li nucleation/plating, optimize the solid electrolyte interface, and mitigate volume change. Consequently, the CoSe₂–NC@CFC can accommodate Li with a high areal capacity of up to 40 mAh cm^–2. Moreover, the Li/CoSe₂–NC@CFC anodes possess outstanding cycling stability and lifespan in symmetric cells, particularly under ultrahigh currents and capacities (1600 h at 10 mA cm⁻²/10 mAh cm⁻² and 5 mA cm⁻²/20 mAh cm⁻²). The Li/CoSe₂–NC@CFC//LiFePO₄ full cell delivers impressive long‐term performance and favorable flexibility. The developed CoSe₂–NC@CFC provides insights into the development of advanced Li hosts for flexible and stable LMAs.

Environment-friendly flexible Cu₂ZnSn(S,Se)₄ (CZTSSe) solar cells show great potentials for indoor photovoltaic market. Indoor lighting is weak and multi-directional, thus the researches of photovoltaic device structures, techniques and performances face new challenges. Here, we design symmetrical bifacial CZTSSe solar cells on flexible Mo-foil substrate to efficiently harvest the indoor energy. Such devices are fabricated by double-sided deposition techniques to ensure bifacial consistency and save cost. We report 9.3% and 9% efficiencies for the front and back sides of the flexible CZTSSe solar cell under the standard sun light. Considering the indoor environment, we verify weak-light response performance of the devices under LED illumination and flexibility properties after thousands of bending. Bifacial CZTSSe solar cells in parallel achieve the superposition of double-sided output current from multi-directional light, significantly enhancing the area utilization rate. The present results and methods are expected to expand indoor photovoltaic applications.