Graphitized porous carbon microspheres assembled with carbon black nanoparticles as improved anode materials in Li-ion batteries

Zhang, Lei; Zhang, Meiju; Wang, Yanhong; Zhang, Zailei; Kan, Guangwei; Wang, Cunguo; Zhong, Ziyi; Su, Fabing

doi:10.1039/c4ta00356j

Cited by 80 publications

(50 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is known that the theoretical capacity of amorphous carbon is around 600.0 mAh g −1 . [ 42 ] Therefore, the theoretical capacity of 30@Si-granadillas, 40@Si-granadillas, and 50@Si-granadillas are calculated to be around 1140.0, 1320.0, and 1680.0 mAh g −1 (based on the TG data). Figure 5 c shows the rate performance of the samples at different current densities.…”

Section: Resultsmentioning

confidence: 99%

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

Zhang

Rajagopalan

Guo

et al. 2015

Adv Funct Materials

Self Cite

204

109

View full text Add to dashboard Cite

A yolk-shell-structured carbon@void@silicon (CVS) anode material in which a void space is created between the inside silicon nanoparticle and the outer carbon shell is considered as a promising candidate for Li-ion cells. Untill now, all the previous yolk-shell composites were fabricated through a templating method, wherein the SiO2 layer acts as a sacrificial layer and creates a void by a selective etching method using toxic hydrofluoric acid. However, this method is complex and toxic. Here, a green and facile synthesis of granadillalike outer carbon coating encapsulated silicon/carbon microspheres which are composed of interconnected carbon framework supported CVS nanobeads is reported. The silicon granadillas are prepared via a modified templating method in which calcium carbonate was selected as a sacrificial layer and acetylene as a carbon precursor. Therefore, the void space inside and among these CVS nanobeads can be formed by removing CaCO3 with diluted hydrochloric acid. As prepared, silicon granadillas having 30% silicon content deliver a reversible capacity of around 1100 mAh g−1 at a current density of 250 mA g−1 after 200 cycles. Besides, this composite exhibits an excellent rate performance of about 830 and 700 mAh g−1 at the current densities of 1000 and 2000 mA g−1, respectively. (≈4200 mAh g −1 ), relatively low discharge potential (≈0.5V vs Li/Li + ), abundance, and environmental benignity. [1][2][3][4][5][6] However, the dramatic volume change (>300%) during lithiation and delithiation processes leads to severe pulverization and continual formation of solid electrolyte interphase (SEI) on the newly formed silicon surfaces, resulting in a large capacity loss. [7][8][9][10][11] Therefore, the cycling performance of silicon-based anodes is still far from satisfactory from a commercial point of view. [ 12 ] Silicon nanoparticles (Si NPs) have been found to tolerate extreme changes in volume with cycling. [ 13 ] Hence, great efforts have been made to improve the cycling stability and electrical conductivity by using various Si-based nanostructures, including Si nanowires, [ 3,14,15 ] porous Si, [16][17][18][19] and conductive agent coated Si such as carbon, [ 18,20,21 ] Ag, [ 22,23 ] and conducting polymer. [ 24 ] Among them, a yolkshell-structured carbon@void@silicon (CVS) composite [ 25,26 ] is quite promising for practical applications, because the void space between the outer carbon shell and the inside Si NP allows the room for volume changes of Si NP without deforming the carbon shell and SEI fi lm, which in turn allows for the growth of a stable SEI on the surface of the outer carbon shell. [ 26 ] Besides, the homogeneous carbon coating shell can prevent the electrolyte ingress and the direct contact of Si NPs with the electrolyte, so the SEI will only be formed on the outer surface of the carbon shell, leading to the high Coulombic effi ciency and improved cycling stability. [ 25 ] For instance, Cui and co-workers achieved a high capacity of ≈2800 mAh g −1 with a very good cycling s...

show abstract

Section: Resultsmentioning

confidence: 99%

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

Zhang

Rajagopalan

Guo

et al. 2015

Adv Funct Materials

Self Cite

204

109

View full text Add to dashboard Cite

show abstract

“…[21][22][23][24][25][26][27][28] It is widely acknowledged that the common porous carbon-based SCs mainly store electrical charges by electrostatic attraction between porous carbons and electrolyte ions. Therefore, the suitable porosity conformation for accumulating more ions and good electrical conductivity for quickly transferring electrons will determine the performance of 5 porous carbon-based SCs 24,29 . As is well known, the rate of electrolyte ion transmission decelerates rapidly with the decreasing temperature, which causes dropped performance of SCs at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

A supercapacitor constructed with a partially graphitized porous carbon and its performance over a wide working temperature range

Liang

Huang

et al. 2015

J. Mater. Chem. A

View full text Add to dashboard Cite

A supercapacitor that possesses excellent performance in a wide temperature range is constructed with a partially graphitized porous carbon (PGPC) as the electrode material and tetraethylammonium tetrafluoroborate/propylene carbonate (Et 4 NBF 4 /PC) as the electrolyte. The PGPC-based electrode shows 10 a very consistent performance at a wide temperature range from -20 to 50 o C. At the working temperatures as high as 50 o C and as low as -20 o C, it delivers the specific capacitances of ~148 and ~135 F g -1 , respectively, and the supercapacitors exhibit high energy densities of ~46 and ~43 Wh kg -1 . Especially, the low-temperature capacitive performance and rate capability of PGPC are much better than the normally used activated carbon and among the best ones for ever-reported carbon-based 15 supercapacitors. More significantly, the PGPC-based supercapacitor shows excellent cycling performance at all tested working temperatures, with a capacitance retention of ~98% after 1000 cycles at 5 A g -1 even when the working temperature decreases to -20 o C.A supercapacitor constructed with a partially graphitized porous carbon (PGPC) as the electrode material and Et 4 NBF 4 /propylene carbonate as the electrolyte exhibits high energy densities of ~46 and ~43 Wh kg -1 at 50 °C and -20 °C, respectively.

show abstract

“…Over the last twenty years, many different carbonaceous materials have been investigated for use in the lithium-ion negative electrodes (e.g., carbon fibers, petroleum coke, and activated carbon). 21,[24][25][26] It is likely that the pulse-power performance of the negative electrode can be optimized with the use of another carbon material (or blends of several carbons) as the second electrochemically active material.…”

Section: Electrode Design Considerations-the Results Inmentioning

confidence: 99%

Theoretical Considerations for Improving the Pulse Power of a Battery through the Addition of a Second Electrochemically Active Material

Knehr

West

2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

Porous electrode theory is used to conduct case studies for when the addition of a second electrochemically active material can improve the pulse-power performance of an electrode. Case studies are conducted for the positive electrode of a sodium metal-halide battery and the graphite negative electrode of a lithium "rocking chair" battery. The replacement of a fraction of the nickel chloride capacity with iron chloride in a sodium metal-halide electrode and the replacement of a fraction of the graphite capacity with carbon black in a lithium-ion negative electrode were both predicted to increase the maximum pulse power by up to 40%. In general, whether or not a second electrochemically active material increases the pulse power depends on the relative importance of ohmic-to-charge transfer resistances within the porous structure, the capacity fraction of the second electrochemically active material, and the kinetic and thermodynamic parameters of the two active materials. To accelerate an electric vehicle, an important requirement of a battery is the ability to deliver high power pulses at all depths of discharge.1-3 Nevertheless, a high power pulse can be difficult to achieve, especially at high depths of discharge (DoD). In some cases, high power is difficult to achieve at high DoD because of an increase in the ohmic resistance during discharge. The ohmic resistance increases due to the movement of the reaction fronts within the electrodes from more favorable (less resistive) to less favorable (more resistive) locations.4,5 For instance, this behavior has been documented in the positive electrode of sodium metal-halide batteries, where the low resistivity of the electrode (nickel and/or iron) and the higher resistivity of the electrolyte (sodium tetrachloroaluminate) cause the reaction front to move from the separator to the current collector during discharge. 6,7 At high DoD, the reaction front is far from the separator and the ionic path length is increased, which increases the overall ohmic resistance in the electrode.One way to improve the pulse-power performance of an electrode is through the addition of a second active material that only reacts at higher DoD.7,8 A schematic of this concept is shown in Figure 1. Part a) shows the discharge and pulse-power process of an electrode with one active material. In this case, the reaction front starts near the separator and moves deeper into the electrode as the cell is discharged. When the electrode is pulsed at the high DoD, the reaction occurs deep within the electrode and there are high ohmic losses due to the increased ionic path length. In contrast, part b) shows the discharge and pulsepower process for an electrode with two active materials. For this case, the same initial behavior is observed, whereby the reaction front moves from the separator to the current collector during discharge. However, during the initial discharge, the second active material does not react. Therefore, when the electrode is pulsed at a high DoD, the high ohmic losses are avoided b...

show abstract

Graphitized porous carbon microspheres assembled with carbon black nanoparticles as improved anode materials in Li-ion batteries

Cited by 80 publications

References 72 publications

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

A supercapacitor constructed with a partially graphitized porous carbon and its performance over a wide working temperature range

Theoretical Considerations for Improving the Pulse Power of a Battery through the Addition of a Second Electrochemically Active Material

Contact Info

Product

Resources

About