Isolated Metalloid Tellurium Atomic Cluster on Nitrogen-Doped Carbon Nanosheet for High-Capacity Rechargeable...

Rechargeable Li-CO₂ battery represents a sustainable technology by virtue of CO₂ recyclability and energy storage capability. Unfortunately, the sluggish mass transport and electron transfer in bulky high-crystalline discharge product of Li₂ CO₃ , severely hinder its practical capacity and rechargeability. Herein, a heterostructure of isolated metalloid Te atomic cluster anchored on N-doped carbon nanosheets is designed (Te_AC @NCNS) as a metal-free cathode for Li-CO₂ battery. X-ray absorption spectroscopy analysis demonstrates that the abundant and dispersed Te active centers can be stabilized by C atoms in form of the covalent bond. The fabricated battery shows an unprecedented full-discharge capacity of 28.35 mAh cm^-2 at 0.05 mA cm^-2 and long-term cycle life of up to 1000 h even at a high cut-off capacity of 1 mAh cm^-2 . A series of ex situ characterizations combined with theoretical calculations demonstrate that the abundant Te atomic clusters acting as active centers can drive the electron redistribution of carbonate via forming TeO bonds, giving rise to poor-crystalline Li₂ CO₃ film during the discharge process. Moreover, the efficient electron transfer between the Te centers and intermediate species is energetically beneficial for nucleation and accelerates the decomposition of Li₂ CO₃ on the Te_AC @NCNS during the discharge/charge process.