Sn-Decorated red P entangled in CNTs as anodes for advanced lithium ion batteries

In Situ Construction of Crumpled Ti3C2Tx Nanosheets Confined S-Doping Red Phosphorus by Ti-O-P Bonds for LIBs Anode with Enhanced Electrochemical Performance

Red phosphorus (RP) with a high theoretical specific capacity (2596 mA h g-1) and a moderate lithiation potential (∼0.7 V vs Li+/Li) holds promise as an anode material for lithium-ion batteries (LIBs), which still confronts discernible challenges, including low electrical conductivity, substantial volumetric expansion of 300%, and the shuttle effect induced by soluble lithium polyphosphide (LixPPs). Here, S-NRP@Ti3C2Tx composites were in situ prepared through a phosphorus-amine-based method, wherein S-doped red phosphorus nanoparticles (S-NRP) grew and anchored on the crumpled Ti3C2Tx nanosheets via Ti-O-P bonds, constructing a three-dimensional porous structure which provides fast channels for ion and electron transport and effectively buffers the volume expansion of RP. Interestingly, based on the results of adsorption experiments of polyphosphate and DFT calculation, Ti3C2Tx with abundant oxygen functional groups delivers a strong chemical adsorption effect on LixPPs, thus suppressing the shuttle effect and reducing irreversible capacity loss. Furthermore, S-doping improved the conductivity of red phosphorus nanoparticles, facilitating Li-P redox kinetics. Hence, the S-NRP@Ti3C2Tx anode demonstrates outstanding rate performance (1824 and 1090 mA h g-1 at 0.2 and 4.0 A g-1, respectively) and superior cycling performance (1401 mAh g-1 after 500 cycles at 2.0 A g-1).

Stable Rooted Solid Electrolyte Interphase for Lithium-Ion Batteries

Metal oxide-based materials are attractive anode candidates for lithium-ion batteries (LIBs) because of their high theoretical capacity. However, these materials suffer from large volume expansion and poor stability of solid electrolyte interphase (SEI) during the charge-discharge process, casusing rapid capacity degradation. Herein, we report that Li₃PO₄-rooted and intact SEI in situ formed on the phosphate-modified SnO₂/CNFs during cycling. The phosphate anions in the anode, could serve as the root to form Li₃PO₄ by bonding with Li ions and participate in the formation of the SEI, thus firmly anchoring and stabilizing the SEI layer. The rooted Li₃PO₄ and enriched LiF in the SEI could synergistically enhance the Li-ion diffusion, significantly reduce the volume expansion, and lead to ultrastable cycling performance over 1100 charge-discharge cycles at 1 A g^-1. This work provides a new avenue for forming stable SEI rooted into the anode and inspires the development of interface engineering toward electrochemical energy storage.