Tunneling‐Gated Metalized Plastic Current Collectors Enabling Autonomous and Reversible Thermal Shutdown in Lithium‐Ion Batteries

ABSTRACT Thermal runaway has constrained the application of high‑energy‑density batteries. Metalized plastic current collectors (MPCCs) offer a promising approach to reducing inactive mass and improving mechanical safety, yet they remain intrinsically passive and provide no active response to thermal abuse. Here, we propose tunneling‑gated thermoresponsive MPCCs (TTMP), which transforms conventional MPCCs from passive conductors into autonomous, self‑protecting components. The TTMP integrates a polyethylene matrix and embedded spiky carbon conductive particles, sandwiched between ultrathin aluminum layers on both surfaces. Upon heating above 100°C, thermal expansion of the polymer disrupts electron tunneling between adjacent spiky carbon particles, sharply suppressing electrical conduction through the TTMP, thereby interrupting current flow and delaying thermally accelerated electrochemical reactions under abuse conditions. When returns to room temperature, electron transport is fully restored, and the battery resumes normal operation. During thermal triggering, the resistance of the TTMP increases from 6.3 Ω to 2.1 × 10 5 Ω within a response time of 4 s. Cells equipped with this collector show a reversible reduction in discharge current of up to 92.5%. Furthermore, 1 Ah pouch cells achieve up to 6 cycles of reversible thermal shutdown with complete performance recovery, while the onset of thermal runaway is delayed by up to 30°C.