Red phosphorus infiltrated into porous C/SiOx derived from rice husks to improve its initial Coulomb efficiency in lithium-ion batteries

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2023-05, Vol.665, p.131180, Article 131180
• Main Authors: Hao, Gengyu, Jiao, Rongji, Deng, Zhengjun, Liu, Yunying, Lan, Dawei, He, Wenxiu, Lang, Zhongmin, Cui, Jinlong
• Format: Article
• Language: English
• Subjects: C/SiOx; Initial Coulomb efficiency; Lithium-ion batteries; Red phosphorus; Rice husks
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2023.131180

To overcome the poor initial Coulombic efficiency (ICE) of C/SiOx anode materials of lithium-ion batteries (LIBs) and promote its industrial application, porous C/SiOx materials have been fabricated by carbonization and activation of rice husks with H3PO4 as an activator. Then, red phosphorus (RP) is infiltrated on the surface and pore inner wall of porous C/SiOx to synthesize RP@C/SiOx using the evaporation-condensation method. In the RP@C/SiOx composite, SiP2 and SiP2O7 generated by the reaction between RP and SiOx particles successfully decrease the formation of inert Li2O and Li4SiO4 during the first Li+ intercalation process. Meanwhile, RP connects with C skeleton to form P-O and P-C bonds during the preparation process, which are conducive to the production of a thin dense solid electrolyte interphase layer. All of these are beneficial to enhance the ICE of C/SiOx. After infiltration of RP, the reversible capacity of porous C/SiOx increased from 435.2 mAh/g to 1147.4 mAh/g at 0.1 A/g, with an ameliorative ICE of 73.6% (51.02% for porous C/SiOx). Even at a higher current density of 2.0 A/g, the considerable specific capacity of 630.0 mAh/g can be obtained after 738.0 cycles. [Display omitted] •SiP2 and SiP2O7 formed by a reaction between RP and SiOx during infiltration process.•P-O and P-C bonds were introduced on the C skeleton of RP@C/SiOx com.posites.•SiP2 and SiP2O7 reduce the formation of inert Li2O and Li4SiO4 in first discharge.•P-O and P-C bonds are conducive to the production of a thin dense SEI layer.•The introduction of RP obviously improves the initial coulombic efficiency of C/SiOx.