Realizing durative flattened and dendrite‐free zinc (Zn) metal configuration is the key to resolving premature battery failure caused by the internal short circuit, which is highly determined by the crystal growth in the electrocrystallization process. Herein, we report that regulating the molecular structure of the inner Helmholtz plane (HIP) can effectively convert the deposition into activation control by weakening the solvated ion adsorption at the interface. The moderated electrochemical reaction kinetics lower than the adatom self‐diffusion rate steers conformal stratiform Zn growth and dominant Zn (0001) texture, achieving crystallographic optimization. Through in situ mediation of electrolyte engineering, orientational plating and stripping behaviors at edge‐sites and tailored solvation structure immensely improve the utilization efficiency and total charge passed of Zn metal, even under extreme conditions, including high areal capacity (3 mAh cm−2) and wide temperature range (−40–60 °C).

The native solid electrolyte interphase (SEI) in lithium metal batteries (LMBs) cannot effectively protect Li metal due to its poor ability to suppress electron tunneling, which may account for the increase of the SEI and even dead Li. It is desirable to introduce artificial electron tunneling barriers (AETBs) with ultrahigh insulativity and chemical stability to maintain a sufficiently low electronic conductivity of the SEI. Herein, a nanodiamond particle (ND)-embedded SEI is constructed by a self-transfer process. The ND serving as the AETB reduces the risk of electron penetration through the SEI, readjusts the electric field at the interface, and eliminates the tip effect. As a result, a dendrite-free morphology and dense massive microstructure of Li deposition are realized even with high areal capacity. Notably, full cells using ultrathin Li anodes (45 μm) and LiNi0.8Co0.1Mn0.1O2 cathodes (4.3 mA h cm–2) can cycle stably over 110 cycles, demonstrating that the AETB-embedded SEI significantly alleviates the anode pulverization and safety concerns in practical LMBs.

The electroactivity of the sulfur composite cathode generally studied requires high electrode porosity, which brings many constraints to the design of lithium–sulfur (Li–S) batteries (e.g., electrolyte quantity and energy density). Here, we focus on electrolyte engineering for highly stable covalent-type sulfurized polyacrylonitrile (SPAN) to realize practical Li–S full batteries with jointly improved volumetric energy density (E v) and cyclability. The conformal polycarbonate cathode-electrolyte interphase (CEI) derived by cyclic carbonate is determined to play a fundamental role in eliminating the fatal shuttle effect, thereby safeguarding the “solid-phase” mechanism of SPAN. The tailored electrolyte also induces a bilayered solid electrolyte interphase (SEI) with enhanced Li+ transport and mechanical strength, which unlocks the compatibility of an ultrathin Li anode. Practical Li-SPAN pouch cells, composed of high-capacity SPAN cathodes (4.08 mAh cm–2) and 1.2× excess Li anodes, can achieve an E v of 615 Wh L–1 and show a cycle life at least 7 times that of the conventional carbonate-based electrolyte.