Coherent manipulation of the lithium plating pattern is at the heart of the safe operation of metallic anodes in the battery technologies. In this article, a lightweight (~0.3 mg cm⁻²), dual-functionalized carbon spheres are anchored onto the Cu foil as the interfacial protective layer via the chelation process of the catechol groups in the polydopamine precursor and the copper foil. The dual-functionalized carbon spheres exhibit the intriguing complementary features: Lithiophilic nitrogen dopants favor the Li⁺ ion absorption and mitigate the nucleation barrier, while the micro/mesopore reservoir spatially homogenizes the ion flux distribution, confining the metallic propagation without dendrite-like protrusions. The metallic anode exhibits an ultra-stable plating/stripping process for 1400 hr with the average Coulombic efficiency of ~99%. A full-cell prototype is constructed by pairing the N-doped carbon spheres on the bare Cu (NCS-Cu) electrode with the high-mass-loading LiVPO₄F (12.5 mg cm⁻²) cathode that can deliver a high energy density of 421.2 Wh kg⁻¹ with the highest power density of 2106 W kg⁻¹ to promise the anode use for high-power/energy-dense metallic batteries.

The ubiquitous implementation of integrated microelectronics requires the on-chip power sources featured with the lightweight configuration design, high areal-capacity-loadings as well as facile reaction kinetics that beyond the current available microbattery prototypes. Herein, this study constructs a mechanically flexible, nanocellulose fiber (NCF) reinforced microbattery configuration, which consists of metal–organic frameworks (ZIF-8) modified NCF as the separator (MOF@NCF), the carbonized MOF@NCF as the metallic deposition substrate (c-MOF@NCF) as well as gradient-structured LiFePO₄ particles infiltrated in the NCF matrix (LFP@NCF) as the cathode. The film-stacked, integrated NCF-based microbattery prototype not only achieves the facile reaction kinetics with homogenized, dendrite-free Li metal deposition at high-capacity-loadings (2 mAh·cm⁻²), but also eliminates the necessary use of metallic current collector to maximize the electroactive mass ratio, which therefore enables the high energy density of 6.8 mWh·cm⁻² at the power output of 1.36 mW·cm⁻² as well as the robust cyclability upon various geometric flexing states. This study presents a quantum leap towards the facile reaction kinetics and multi-scale interfacial stability for the flexible microbattery construction that based on the sustainable utilization of bio-scaffolds.

The practical deployment of metallic anodes in the energy-dense batteries is impeded by the thermodynamically unstable interphase in contact with the aprotic electrolyte, structural collapse of the substrates as well as their insufficient affinity toward the metallic deposits. Herein, the mechanical flexible, lightweight (1.2 mg cm⁻²) carbon nanofiber scaffold with the monodispersed, ultrafine Sn₄P₃ nanoparticles encapsulation (Sn₄P₃NPs@CNF) is proposed as the deposition substrate toward the high-areal-capacity sodium loadings up to 4 mAh cm⁻². First-principles calculations manifest that the alloy intermediates, namely the Na₁₅Sn₄ and Na₃P matrix, exhibit the intimate Na affinity as the “sodiophilic” sites. Meanwhile, the porous CNF regulates the heterogeneous alloying process and confines the deposit propagation along the nanofiber orientation. With the precise control of pairing mode with the NaVPO₄F cathode (8.7 mg cm⁻²), the practical feasibility of the Sn₄P₃ NPs@CNF anode (1^* Na excess) is demonstrated in 2 mAh single-layer pouch cell prototype, which achieves the 95.7% capacity retention for 150 cycles at various mechanical flexing states as well as balanced energy/power densities.