Fast Charge–Discharge of LiNi _0.9 Co _0.05 Mn _0.05 Enabled by a Bikitaite‐Infused Separator for Li Metal Batteries

ABSTRACT Lithium‐metal batteries (LMBs) offer exceptional theoretical energy densities, making them a promising option for next‐generation energy storage. However, their widespread use is hindered by Li dendrite formation and unstable electrode–electrolyte interfaces. Herein, we present a bikitaite‐infused cellulose‐based separator (CBT) designed to regulate Li + ion transport and support stable Li‐metal deposition. The separator combines the mechanical flexibility and porosity of cellulose with the ion‐conductive, nanoporous properties of bikitaite zeolite, forming continuous 3D Li + transport pathways and improving electrolyte wettability. Electrochemical tests reveal a high Li + ion transference number of 0.742 and ionic conductivity (3.45 × 10 − 3 S cm − 1 ), reducing polarization and enhancing charge‐transfer kinetics. Consequently, symmetric Li||Li cells exhibit stable cycling for over 2200 h with low‐voltage hysteresis. In Li||NCM90 full cells, the CBT separator enables excellent rate performance and retains ∼60% capacity after 2500 cycles at 2C/4C rates. It also demonstrates outstanding thermal resilience and electrochemical function at –25°C due to efficient Li + ion desolvation. The findings of this study highlight CBT separators as a scalable, cost‐effective solution to improve the safety and longevity of Li metal batteries.