Lithium metal batteries (LMBs) as the next generation promising high energy density alternatives among electrochemical storage technologies have received worldwide attention. However, the incompatibility between metallic lithium and traditional liquid...

The development of high energy density lithium metal batteries has been retarded by the uncontrolled lithium dendrite formation and unstable Ni‐rich cathode–electrolyte interface (CEI). Herein, the bidirectionally functional polymer electrolytes (BDFPE) are designed via direct UV solidification of functional polymer species on electrode surfaces to simultaneously handle the interface issues faced by anodes and cathodes. By constructing the BDFPE, a smooth and dendrite‐free lithium deposition is enabled for Li||Li symmetry cells after 1800 h ultralong cycling at 1 mA cm−2 and 1 mAh cm−2, which are attributed to the fast ion conductivity (5.84 × 10−4 S cm−1), high Li+ transfer number (0.69) of BDFPE and low interfacial resistance between electrode and solid electrolytes. Furthermore, Li||LiNi0.6Co0.2Mn0.2O2 batteries demonstrate a favorable cycling and rate capability, and a stable and phosphate‐based CEI layer is constructed in situ. DFT studies reveal that the functional additives FEC and TEP participate in the interface formation. The finding provides a promising design strategy to accommodate the anode and cathode interfaces for high energy density lithium metal batteries.

Among all energy storage systems, lithium metal batteries (LMBs) show great advantages in terms of energy density. Nevertheless, the challenges of lithium metal anodes, namely, dendrite formation and low Coulombic efficiency, hinder the practical application of LMBs. In this work, we used the ZnO/carbon shell/carbon cloth as a host for the lithium metal anode. The introduction of ZnO sites reduces the nucleation barrier of lithium deposition, and the existence of a 3D current collector alleviates the volume change during lithium plating/stripping. In addition, the combination of ZnO/C and 3D carbon cloth decreases the local current density and contributes to uniform lithium plating/stripping. The half cells assembled with modified carbon cloth electrodes cycle for more than 125 cycles with a high Coulombic efficiency of 99.34%, even under a high areal capacity of 6 mA h cm–2. By and large, our work provides a simple and effective strategy to modify the current collector for high Li-content anodes.

High-energy-density lithium metal batteries with high safety and stability are urgently needed. Designing the novel nonflammable electrolytes possessing superior interface compatibility and stability is critical to achieve the stable cycling of battery. Herein, the functional additive dimethyl allyl-phosphate and fluoroethylene carbonate were introduced to triethyl phosphate electrolytes to stabilize the deposition of metallic lithium and accommodate the electrode–electrolyte interface. In comparison with traditional carbonate electrolyte, the designed electrolyte shows high thermostability and inflaming retarding characteristics. Meanwhile, the Li||Li symmetrical batteries with designed phosphonic-based electrolytes exhibit a superior cycling stability of 700 h at the condition of 0.2 mA cm−2, 0.2 mAh cm−2. Additionally, the smooth- and dense-deposited morphology was observed on an cycled Li anode surface, demonstrating that the designed electrolytes show better interface compatibility with metallic lithium anodes. The Li||LiNi0.8Co0.1Mn0.1O2 and Li||LiNi0.6Co0.2Mn0.2O2 batteries paired with phosphonic-based electrolytes show better cycling stability after 200 and 450 cycles at the rate of 0.2 C, respectively. Our work provides a new way to ameliorate nonflammable electrolytes in advanced energy storage systems.