实时磁性测试深入理解锂离子电池中的过渡金属催化作用

催化剂由于具有降低电化学过电位和改善动力学条件的能力,在各种储能器件中起着至关重要的作用.在锂离子电池中,首圈放电过程中形成的固体电解质界面膜,通常被认为是一旦形成就稳定不分解的.而在过渡金属的催化下,这种电解质分解衍生的聚合物凝胶状膜(PGF)能可逆地形成和分解.这种过渡金属催化机制可以进行催化储锂,即形成的PGF具...

Transition metal catalysis in lithium-ion batteries studied by operando magnetometry

Owing to the potential ability of metal nanoparticles to enhance the performance of energy storage devices, their catalytic performance has been studied by many researchers. However, a limited number of suitable characterization techniques does not allow fully elucidating their catalytic mechanism. Herein, high-accuracy operando magnetometry is employed to investigate the catalytic properties of a cobalt oxide electrode for lithium-ion batteries fabricated by magnetron sputtering. Using this technique, the magnetic responses generated by the Co-catalyzed reversible formation and decomposition of a polymer/gel-like film are successfully detected. A series of CoO/Co films are prepared by magnetron sputtering in different environments at various sputtering times to study the influence of Co content and film thickness on their catalytic properties. It is clearly demonstrat-ed that increasing the Co content enhances the magnetic signal associated with the catalysis pro-cess. Furthermore, decreasing the electrode thickness increases the area affected by the catalytic reactions, which in turn enhances the corresponding magnetic responses. The obtained results experimentally confirm the catalytic activity of Co metal nanoparticles and provide a scientific guidance for designing advanced energy storage devices. This work also shows that operando mag-netometry is a versatile technique for studying the catalytic effects of transition metals.