Solution Synthesis of Iodine-Doped Red Phosphorus Nanoparticles for Lithium-Ion Battery Anodes

Abstract

Red phosphorus (RP) is a promising anode material for lithium-ion batteries due to its earth abundance and a high theoretical capacity of 2596 mA h g. Although RP-based anodes for lithium-ion batteries have been reported, they were all in the form of carbon-P composites, including P-graphene, P-graphite, P-carbon nanotubes (CNTs), and P-carbon black, to improve P's extremely low conductivity and large volume change during cycling process. Here, we report the large-scale synthesis of red phosphorus nanoparticles (RPNPs) with sizes ranging from 100 to 200 nm by reacting PI with ethylene glycol in the presence of cetyltrimethylammonium bromide (CTAB) in ambient environment. Unlike the insulator behavior of commercial RP (conductivity of <10 S m), the conductivity of RPNPs is between 2.62 × 10 and 1.81 × 10 S m, which is close to that of semiconductor germanium (1.02 × 10 S m), and 2 orders of magnitude higher than silicon (5.35 × 10 S m). Around 3-5 wt % of iodine-doping was found in RPNPs, which was speculated as the key to significantly improve the conductivity of RPNPs. The significantly improved conductivity of RPNPs and their uniform colloidal nanostructures enable them to be used solely as active materials for LIBs anodes. The RPNPs electrodes exhibit a high specific capacity of 1700 mA h g (0.2 C after 100 cycles, 1 C = 2000 mA g), long cycling life (∼900 mA h g after 500 cycles at 1 C), and outstanding rate capability (175 mA h g at the charge current density of 120 A g, 60 C). Moreover, as a proof-of-concept example, pouch-type full cells using RPNPs anodes and Li(NiCoMn)O (NCM-532) cathodes were assembled to show their practical uses.

Fabrication of One‐Dimensional Mesoporous CoP Nanorods as Anode Materials for Lithium‐Ion Batteries

“…0.57 V can be attributed to the generation of SEI film and the insertion of Li + ions. In the anodic process, the peak at around 1.15 V resulted from the lithium‐extraction reaction . In subsequent cathodic/anodic cycles, the R‐P electrode shows the continuous lithium insertion/extraction process, without apparent peaks.…”

“…In recent years, phosphorus‐based anodes have aroused extensive interest, due to their promising features of abundance, suitable redox potential, and high theoretical specific capacity , . Among them, nontoxic, inexpensive, and chemically durable red phosphorus (R‐P) exhibits a high theoretical capacity of 2595 mAh g –1 .…”

Advanced Phosphorus‐Based Materials for Lithium/Sodium‐Ion Batteries: Recent Developments and Future Perspectives

“…2018, 8, 1702849 Figure 6. [163] Copyright 2017, American Chemical Society. b) Schematic illustration of the C@P/GA electrode in the SIB system.…”

“…Accordingly, it exhibits superior electrochemical properties, especially excellent cycling performance (Figure 7f). [163] The solution-phase approach for the large scale RPNPs growth avoids high portion of carbon in active materials and makes particle size controllable, while it is easy to bring in impurities which is difficult to be removed. Recently, a solution-phase approach to synthesize iodine-doped RP nanoparticles (RPNPs) by reacting PI 3 with ethylene glycol in the presence of cetyltrimethylammonium bromide (CTAB) has been demonstrated (Figure 7g).…”

All graphene electrode for high‐performance asymmetric supercapacitor

“…Adopting fast surface electrode reaction sustaining high energy density at once is one of the effective approaches to solve the abovementioned challenges. 38 Graphene can be doped by different elements including B, N, S, and P. 39 Electrical conductivity and cyclic stability is enhanced by heterotopic doping due to the structural defects and/or enlarged lattice distance. Monolayer graphene is a competent material for developing highly capacitive hybrid energy storage devices, owing to its extraordinary electrical conductivity, large specific surface area (SSA), and inherent flexibility and tunable structure.…”