Built-in-field-regulated low-temperature failure in LiFePO₄ cathodes through joule-heating-induced riveting engineering

LiFePO₄ batteries suffer from sluggish charge transfer, severe polarization, and reaction heterogeneity at low temperatures. In this work, a Joule-Heating-Driven Riveting strategy constructs a Zn-mediated surface-bulk coupled architecture for low-temperature electrochemical modulation. Mechanically assisted surface assembly followed by ultrafast Joule heating integrates anchored Zn-containing domains with near-surface lattice reconstruction, creating a built-in electric field and a favorable electronic environment for Li⁺ extraction/insertion. The modified LiFePO₄ exhibits at −20 °C across a broad rate range higher reversible capacity, reduced voltage hysteresis, and superior cycling durability. Mechanistic studies reveal accelerated kinetics, enhanced solid-solution behavior, and suppressed structural fluctuation, alleviating polarization-induced phase heterogeneity. In pouch full cells, the cathode shows lower resistance increase, stable output, and uniform stress evolution. Post-cycling and simulation analyses confirm reduced side reactions, mitigated local stress, and homogeneous lithium distribution. This work presents an effective cathode-engineering strategy for low-temperature LiFePO₄ batteries and a scalable route for cold-tolerant polyanion cathodes.