Verifying the Rechargeability of Li‐CO2 Batteries on Working Cathodes of Ni Nanoparticles Highly Dispersed on N‐Doped Graphene

Abstract

Li‐CO 2 batteries could skillfully combine the reduction of “greenhouse effect” with energy storage systems. However, Li‐CO 2 batteries still suffer from unsatisfactory electrochemical performances and their rechargeability is challenged. Here, it is reported that a composite of Ni nanoparticles highly dispersed on N‐doped graphene (Ni‐NG) with 3D porous structure, exhibits a superior discharge capacity of 17 625 mA h g−1, as the air cathode for Li‐CO 2 batteries. The batteries with these highly efficient cathodes could sustain 100 cycles at a cutoff capacity of 1000 mA h g−1 with low overpotentials at the current density of 100 mA g−1. Particularly, the Ni‐NG cathodes allow to observe the appearance/disappearance of agglomerated Li 2 CO 3 particles and carbon thin films directly upon discharge/charge processes. In addition, the recycle of CO 2 is detected through in situ differential electrochemical mass spectrometry. This is a critical step to verify the electrochemical rechargeability of Li‐CO 2 batteries. Also, first‐principles computations further prove that Ni nanoparticles are active sites for the reaction of Li and CO 2, which could guide to design more advantageous catalysts for rechargeable Li‐CO 2 batteries.