Cr₂O₃nanosheet/carbon cloth anode with strong interaction and fast charge transfer for pseudocapacitive energy storage in lithium-ion batteries

Abstract

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.

Green and Scalable Fabrication of Sandwich-like NG/SiOx/NG Homogenous Hybrids for Superior Lithium-Ion Batteries

“…Smaller R f and R ct values ( Table S2 ) of the Li//NG/SiO x /NG cell than those of the Li//G/SiO x /G cell indicated the enhanced conductivity of the NG/SiO x /NG composite by N doping, which resulted in its fast electrode kinetics [ 3 , 10 , 17 , 52 ]. Slope lines in the low-frequency region are ascribed to Warburg impedance (Z w ), which is associated with Li + diffusion in bulk electrode materials [ 18 , 47 , 54 ]. And the lithium ion diffusion coefficient (D Li+ ) could be calculated with Equation (4) through linear fitting between Z’ and ω −1/2 (ω = 2πf) in low frequencies of Nyquist diagrams [ 1 , 3 ].…”

“…According to Equation (4), for a given electrode, the σ −2 value is proportional to D Li+ while all the other parameters are constants [ 1 , 18 , 55 ]. The much smaller σ −2 values ( Table S2 ) of the NG/SiO x /NG electrode indicated the faster diffusion of the Li + in NG/SiO x /NG electrode [ 53 , 54 , 56 ]. The lower electrode impedance and faster diffusion of Li + contributed to the enhanced electrochemical capacity and rate capability of the NG/SiO x /NG electrode.…”

“…The power-law relationship between the measured current (i) and sweep rates (v) is generally expressed as Equation (5), where a and b are adjustable parameters [1,43,57,59]. The b values could be determined by slopes of log (v) − log (i) plots, and two typical b values of 1 and 0.5 indicated that the electrode was dominated by capacitive behaviors and diffusive behaviors, respectively [45,54,57]. The calculated b values at low potentials are 0.72 and 0.55 in the NG/SiO x /NG and G/SiO x /G electrodes (Figure 6c), indicating the hybrid contributions of diffusion-controlled behavior and capacitance-controlled behavior to the total capacity; and the larger b value for the NG/SiO x /NG electrode sug-gested that the charge storage was mainly dominated by surface capacitance-controlled behavior, which would result in a faster electrode kinetic [23,29,52].…”

A Comprehensive Review of Graphene-Based Anode Materials for Lithium-ion Capacitors

“…Nb-based materials, typical intercalation-type compounds with high specific capacity, exceptional rate capability and cycling stability, are emerging as excellent anodes for LICs. Recent reports demonstrated that transition metal-based compounds with novel nanostructure displayed intercalation pseudocapacitive characteristics, making them promising anode materials to bridge the kinetics gap with the capacitor-type cathodes [86][87][88]. Among these materials, orthorhombic Nb 2 O 5 has even more attractive rate and cycling performances due to the features of unique pseudocapacitive intercalation mechanism and rapid Li + transport throughout a-b plane without any phase transformation [89].…”

Review on carbonaceous materials and metal composites in deformable electrodes for flexible lithium-ion batteries

“…A combination of hydrothermal treatment and subsequent 3 h of heat treatment in air at 500 °C has used to fabricate freestanding Cr 2 O 3 nanosheets/CC flexible anodes. 126 The large surface area with better contact of active material with electrolyte improves the rate of Li-ion diffusion. Consequently, the hybrid anode delivered a high discharge capacity with good retention (1547.8 mA h g −1 at 0.1 A g −1 and retained 917.3 mA h g −1 after 200 cycles), and also demonstrated a specific capacity of 414.2 mA h g −1 after 400 cycles at 800 mA g −1 .…”