Low‐Temperature Charge/Discharge of Rechargeable Battery Realized by Intercalation Pseudocapacitive Behavior

Conventional intercalation compounds for lithium‐ion batteries (LIBs) suffer from rapid capacity fading and are even unable to charge–discharge with temperature decline, owing to the sluggish kinetics and solvation/desolvation process. In this work, a high‐performance rechargeable battery at ultralow temperature is developed by employing a nanosized Ni‐based Prussian blue (NiHCF) cathode. The battery delivers a high capacity retention of 89% (low temperature of −50 °C) and 82% (ultralow temperature of −70 °C) compared with that at +25 °C. Various characterizations and electrochemical investigations, including operando Fourier transform infrared spectra, in situ X‐ray diffraction, cyclic voltammetry response, and galvanostatic intermittent titration technique are carried out to detect the structural stability and electrochemical behavior at different temperatures. It turns out that the pseudocapacitive behavior drives the desolvation process at the interface, while fast diffusion in the bulk electrode accelerates the movement of Li(+) from the interface to the bulk materials. The unique synergistic features of intercalation pseudocapacitance at the electrolyte/electrode interface and high diffusion coefficient in the bulk electrode enables the NiHCF cathode with excellent low temperature performance. These findings offer a new direction for the design of LIBs operated at low temperature.