Engineering red phosphorus confined in TiO_2-coated ultrathin carbon-bubble foam with enhanced Li~+ storage capability

摘要

Red phosphorus (RP), as one of the most promising anode materials for lithium-ion batteries, attracts much attention for its high theoretical specific capacity, cost-effective, and commercial availability. However, poor cycling stability and rate capability caused by huge volume expansion and low intrinsic electronic conductivity hinder the commercialization of RP-based anode. Herein, RP confined in ultrathin hollow carbon-bubble-constructed foam (RP-HC) is developed to improve electronic conductivity and mechanical structure stability. Additionally, low-temperature atomic layer deposition (LT-ALD) technology is adopted to further modify the surface of the RP-HC, forming a core-shell RP-HC@TiO2 structure with about 5 nm TiO2 coating layer. Benefiting from the dual confinement of TiO2 buffer layer and conductive porous carbon host with effective P-O-C bond, the RP-HC(70%)@TiO2 electrode delivers an outstanding cycling performance (795.2 mAh g(-1) after 200 cycles at 100 mA g(-1)) and rate capability (459.9 mAh g(-1) at 2000 mA g(-1), almost 1.6 times and 12 times relative to RP-HC(70%) and RP under the same test condition). In-situ electrochemical impedance spectroscopy analyses are also conducted to investigate the superior Li+ storage properties of the RP-HC@TiO2.