A Micro‐Cracked Conductive Layer Made of Multiwalled Carbon Nanotubes for Lithium‐Ion Batteries

A conductive layer, made of multiwalled carbon nanotubes (MWCNTs), with micro‐cracks and a micro/nanoporous structure is fabricated between an active material layer (AML) and a current collector. The coating thickness of the MWCNT‐based conductive layer (MCL) varies in the range of 25–100 μm. Electrochemical tests of half‐cells demonstrate that both the mesocarbon‐microbeads (MCMB) anode and the LiCoO2 cathode with a micro‐cracked MCL show higher capacity, lower impedance, and less capacity fading than the pristine and non‐cracked electrodes. These improvements are caused by the enhancement of adhesion strength and the buffer effect of the micro‐cracked MCL. With a change of the coating thickness, the size and number of micro‐cracks on the MCL varies to accommodate the active material with different particle sizes. The electrodes with a micro‐cracked MCL with a coating thickness of 50 and 75 μm are suitable for MCMB and LiCoO2 with a particle size of 10–20 μm. A multiwalled carbon nanotube (MWCNT)‐based conductive layer (MCL) with micro‐cracked porous structure is used as a functional buffer layer between the active material and current collector. The micro‐cracked MCL is synthesized by coating incompletely dispersed MWCNT binder slurry. The effects on the electrochemical performance of both the anode and cathode of lithium‐ion batteries are evaluated.