Synergistic engineering of defects and architecture in Co_3O_4@C nanosheets toward Li/Na ion batteries with enhanced pseudocapacitances

摘要

Constructing robust 2D-based energy storage nanomaterials by well-defined pore architectures and rational surface modification are critical yet daunting challenges for rechargeable alkali-ion batteries.Herein,a new -type 2D interwoven multi pores decorated Co_3O_4@N-doped carbon nanosheet with rich surface defects is proposed as lithium/sodium ion anodes for the first time.The combining experimental researches,microscopic structure characterization and dynamics analysis demonstrate that the multi porous structure provides large numbers of channels to accelerate Li~+/Na~+ transport,rational surface design creates abundant active sites for fast ions reactions,while robust carbon shell offers excellent ionic/electrical conductivity and structural integrity.The obtained bifunctional composites deliver superior rate performance and long-term cycle stability (~529 mA h g~(-1) after 2000 cycles in LIBs and ~166 mA h g~(-1) after 1700 cycles in SIBs) due to the synergistic contribution of the unique structure and surface defects.Furthermore,it still remains a high reversible capacity (>610 mA h g~(-1) after 1000 cycles) in full cell.Kinetic analysis reveals the designed anode exhibits prominent pseudocapacitive behavior,enabling ultra-fast lithium/sodium storage and ultrahigh-rate capability.This work offers valuable insights for developing high performance energy storage devices.