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.

Germanium phosphide is a potential anode material because of its high theoretical capacity and incredible rate capability on lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). However, the huge volume change that occurs while germanium phosphide is converted to Na3P or Li3P directly leads to poor cyclability and limits further applications. Herein, mesoporous germanium phosphide (MGeP x ) microspheres with diameter size ranging from 0.5 to 1.5 μm were first prepared by a one-step and template-free approach. MGeP x microspheres were composed of nanoparticles of around 10 nm with a narrow distribution of pore sizes of around 4 nm. The MGeP x possessed superior features in LIBs/SIBs since it shortens the diffusion path of the energy carrier and provides the buffer space for the transport of Li/Na ions. MGeP x showed attractive electrochemical properties as a potential anode candidate, such as a high first-cycle Coulombic efficiency of 82.63%, high reversible capacity (1400 mA h g–1 after 150 cycles at 0.2 C), excellent ultrahigh rate capacity (370 mA h g–1 at 72 A g–1, 40 C), and stable cycling performance (450 cycles at 1 C) in the LIBs and high reversible capacity (704 mA h g–1 after 100 cycles at 0.2 C) and stable cycling performance (200 cycles at 0.6 C) in SIBs.