3D Interconnected Porous Graphene Sheets Loaded with Cobalt Oxide Nanoparticles for Lithium‐Ion Battery Anodes

Abstract

Nanomaterials with high surface‐to‐volume ratio and tunable electronic and optical properties have expanded their use in variety of applications, especially energy conversion and storage. Here we report on the synthesis of a cobalt oxide (Co3O4)/3D‐interconnected porous graphene (PG) nanocomposite by using a simple solvothermal route and its application as a Li‐ion battery anode. Among the different compositions investigated, the composite PG‐600 (with 50 % PG) showed a discharge capacity of 700 mAh g−1 at a current density of 500 mA g−1 and maintained 90 % retention after 80 cycles. The high surface area of the 3D PG sheets helps the Co3O4 nanoparticles to form a uniform dispersion on the surfaces. The increased surface area (accessibility) and electrical conductivity of the composite result in significant enhancement in the capacity, cycling stability, and rate capability than the native Co3O4 phase.

Functional Groups and Pore Size Distribution Do Matter to Hierarchically Porous Carbons as High-Rate-Performance Supercapacitors

“…The Ragone plot given in Figure 3g compares the energy density and power density of a PEA-Zn-700-40 electrode based on active material loading in a two-electrode cell with those of the other carbon materials. [43,55,58,[59][60][61][62][63][64][65][66][67][68][69][70] At a long current drain time of 310 s, the values of the energy and power densities of PEA-Zn-700-40 based capacitor are 10.3 Wh kg -1 and 122 W kg -1 , respectively, and at a time of 3.6 s, E = 4.89 Wh kg -1 , P = 4903 W kg -1 . It is clear that PEA-Zn-700-40 exhibits much better in terms of both energy density and power density than other common ACs.…”

Conversion-type Anode Materials for Alkali-Ion Batteries: State of the Art and Possible Research Directions

“…25,26 (d) Intermittency of sloping and small plateau regions in the discharge profile (graphene/Co 3 O 4 ). 27 (e) Larger irreversible capacity loss and attendant initial low Columbic efficiency in Fe 2 O 3 conversion material. 25 (f) Drastic decrease in capacity of conversion materials compared to alloying materials 28 (reprinted with permission from refs (24−27), and (28)).…”

“…Various issues associated with conversion materials through relevant data from the literature: (a) Voltage hysteresis and its various components . (b, c) Inconsistent cycling behavior {drastic decrease (CuCo 2 O 4 nanowalls) and continuous increase (mixed MnCoOx)} observed in conversion materials. , (d) Intermittency of sloping and small plateau regions in the discharge profile (graphene/Co 3 O 4 ) . (e) Larger irreversible capacity loss and attendant initial low Columbic efficiency in Fe 2 O 3 conversion material .…”

Carbon‐Encapsulated SnO2 Core–Shell Nanowires Directly Grown on Reduced Graphene Oxide Sheets for High‐Performance Li‐Ion Battery Electrodes

“…However, in spite of the superior theoretical charge/discharge capacity of such materials when compared to graphitic ones, their large volume expansion during repetitive lithiation/delithiation processes unfortunately results in poor cycling performance, and they also suffer from intrinsically low electrical conductivity, which obstructs the practical implementation of these electrode materials. Over the past few years, a number of studies have focused on carbon‐based additives (e.g., carbon nanoparticles, carbon nanotubes, and graphene nanosheets) in order to resolve the intrinsic issues of the electrode materials because the carbon additive materials can offer conductive pathways and flexible buffer matrices, thereby improving the charge/discharge cycling behaviors of the electrode materials . However, in most cases, the electrode materials with such carbon additives have been processed into heavy slurry composites together with conductive enhancers and polymeric binders, and the slurry mixtures have been casted onto current collectors.…”

“…[8][9][10][11] However, in spite of the superiortheoretical charge/discharge capacity of such materials when compared to graphitic ones,t heir large volume expansion during repetitive lithiation/delithiation processes unfortunately results in poor cycling performance,a nd they also suffer from intrinsically low electrical conductivity, which obstructs the practical implementation of these electrode materials.O ver the past few years,anumber of studies have focused on carbon-based additives (e.g.,c arbon nanoparticles, carbon nanotubes,a nd graphene nanosheets) in order to resolve the intrinsic issues of the electrodem aterials because the carbon additive materials can offer conductive pathways and flexible buffer matrices,t hereby improving the charge/discharge cycling behaviorso ft he electrodem aterials. [12][13][14][15][16][17][18][19][20] However, in most cases,t he electrode materials with such carbon additives have been processed into heavy slurry composites togetherw ith conductive enhancers and polymeric binders,and the slurry mixtures have been casted onto current collectors. Thes lurry-castede lectrodes might be able to hinder the carbon-based additives from displaying their maximized effect on the electrochemical performances because they tend to be detached from current collectors by harsh andrepeated charge/discharge cycles and to cause inefficiencyi nb oth the mass and charge transport within the electrodes tructures,t hus leading to ad ecline in battery performance.I nt his regard,a ne fficient design of such carbonbased additive materials inevitably needs to be proposed for developinghigh-performance battery electrode platforms.…”