Control of nanoparticle dispersion, SEI composition, and electrode morphology enables long cycle life in high silicon content nanoparticle-based composite anodes for lithium-ion batteries

Abstract

Striking a balance between high theoretical capacity, Earth abundance, and compatibility with existing manufacturing infrastructure, silicon is one of the few materials that meets the requirements for a next-generation anode...

Pitch Carbon‐coated Ultrasmall Si Nanoparticle Lithium‐ion Battery Anodes Exhibiting Reduced Reactivity with Carbonate‐based Electrolyte

“…We have previously reported on the specific parameters used to produce different sized Si NPs, [23] including the D50 = 5.9 nm Si NPs used herein. [11] Briefly, SiH 4 , Ar, and H 2 were flown through a 19 mm ID/25 mm OD quartz or alumina reactor tube at 20, 20, and 250 standard cubic centimeters per minute, respectively. The reactor maintained a capacitively-coupled plasma at 3 Torr between a copper ring electrode and grounded electrode positioned 10 mm downstream using an advanced Energy Cesar 136 generator applying 250 W of forward RF power at 13.56 MHz through an Advanced Energy VM1000 matching network (tuned to give a reflected power of 0-1 W).…”

“…We used a custom nonthermal RF‐enhanced plasma reactor first reported by Kortshagen and coworkers [22] to produce the Si NPs. We have previously reported on the specific parameters used to produce different sized Si NPs, [23] including the D50=5.9 nm Si NPs used herein [11] . Briefly, SiH 4 , Ar, and H 2 were flown through a 19 mm ID/25 mm OD quartz or alumina reactor tube at 20, 20, and 250 standard cubic centimeters per minute, respectively.…”

“…[9] Our team also has published several examples of alternative approaches based on molecular rather than bulk carbonaceous coatings targeting this strategy, [10] some of which exhibit highly promising performance. [11] Here, we present the fabrication of a Si/pitch composite material that meets the above criteria, where ultrasmall diameter (d = 5.9 nm) Si nanoparticles (NPs) are coated with pitch carbon to form a Si/pitch composite. Si particles less than 10 nm are not only below the 150 nm threshold identified for single particle fracture but are equivalent to the size that the Si domains will inevitably reach when cycled in a carbonate-based electrolyte.…”

“…There are examples of materials that satisfy the criteria of both appropriately small Si particles of less than 10 nm and with carbon‐coatings, [8] including a promising material that is synthesized by impregnating a micron sized nano‐porous silicon particle with petroleum pitch followed by carbonization [9] . Our team also has published several examples of alternative approaches based on molecular rather than bulk carbonaceous coatings targeting this strategy, [10] some of which exhibit highly promising performance [11] …”

Boron–Silicon Alloy Nanoparticles as a Promising New Material in Lithium-Ion Battery Anodes

“…The synthesis and characterization of these electrodes has been described previously. 46 Figure 3a shows the data for half-cell cycling of a BSi@ Li 2 CO 3 anode with 1.2 M LiPF 6 in 3:7 ethylcarbonate:ethylmethyl carbonate with 3 wt % fluoroethylene carbonate (GenF3) as the electrolyte and Li metal as the counter electrode. The composite anode produces a first cycle delithiation gravimetric capacity of 1250 mAh/g from lithiating to 0.01 V and delithiating to 1.5 V and a Coulombic efficiency (CE) of 74%.…”