Laser Thermal Shock Enabling Ultrafast Spin Regulation of MnO₂ for Robust Pseudocapacitive Energy Storage

Abstract

The pseudocapacitive performance of MnO2 is intrinsically determined by its electronic structure, especially the spin state. However, the correlation between the electrochemical behavior and the spin state of electrode materials remains ill‐defined, and efficient spin regulation strategies for MnO2 are thus lacking. Herein, the study reports laser thermal shock of electrochemically deposited MnO2 for efficient spin regulation. The combined use of theoretical calculation and experimental investigation indicates that the thermal shock induces oxygen vacancy in MnO2 to reduce spin polarization and delocalize electron distribution. As a result, the electrical conductivity largely increases and the Na+ adsorption is reasonably optimized. By lasering an integrated electrode for only 83 s, a 54% increase of the specific capacitance is observed. For the first time, the pseudocapacitive capability of MnO2 is revealed by in situ electron paramagnetic resonance where the enhanced redox pair is correlated with evolution of Mn2+ during charge/discharge. Moreover, the commercial‐level mass‐loaded electrode also offers a decent performance enhancement after laser treatment, indicating the great prospect of this technology for real applications. This work innovatively correlates the pseudocapacitive performance of MnO2 with its spin state and offers a new avenue to optimize the electrochemical capability through spin regulation.