Cr 2 O 3 nanosheet/carbon cloth anode with strong interaction and fast charge transfer for pseudocapacitive energy storage in lithium-ion batteries.

Flexible lithium-ion batteries have attracted considerable interest for next-generation bendable, implantable and wearable electronics devices. Here, we have successfully grown Cr 2 O 3 nanosheets on carbon cloth (CC) as freestanding anodes for Li-ion batteries (LIBs). Density functional theory (DFT) calculations verify an optimal structure of two-dimensional Cr 2 O 3 nanosheets on the carbon fiber surface and a strong interaction between the O edges of Cr 2 O 3 and the carbon. The interconnected Cr 2 O 3 nanosheets with a large surface area enable fast charge transfer by efficient contact with electrolyte while the flexible CC substrate accommodates the volume change during cycles, leading to excellent rate capability and cyclic stability through psuedocapacitance-dominant energy storage. Full cells are assembled using the Cr 2 O 3 -CC anode and a LiFePO 4 cathode, which deliver excellent capacity retention and rate capability. The fully-charged cell is demonstrated to power a red light-emitting diode (LED), verifying the potential of Cr 2 O 3 -CC as a promising anode material for LIBs.