Nanoparticle-assembled interconnected PbO1.44 hollow spheres enabled by PVP-driven transformation of β-PbO2 and self-sacrificial templating for superior lithium storage

Nanoscale. 2024 Dec 24. doi: 10.1039/d4nr04763j. Online ahead of print.

Abstract

Lead oxides (PbOx, 1 ≤ x ≤ 2) are promising high-capacity and low-cost anodes for lithium ion batteries (LIBs). However, the huge lithiation-induced volume expansion of conventional large-sized PbOx particles leads to severe electrode pulverization with poor cycling stability. Herein, a rare mixed-valence PbO1.44 with a unique hierarchical architecture of nanoparticle-assembled interconnected hollow spheres (denoted PbO1.44 NAHSs) is crafted by introducing polyvinylpyrrolidone (PVP) into the solution of generating β-PbO2 microspheres (MSs), which is exploited for the first time as a potential advanced anode material for LIBs. Notably, an intriguing PVP-driven dissolution-recrystallization transformation process converting β-PbO2 MSs into PbO1.44 NAHSs is revealed by PVP-concentration and reaction-time control experiments, demonstrating the dual function of PVP as a mild reducing agent combined with it being a morphology regulator for the construction of PbO1.44 NAHSs. Furthermore, a self-sacrificial templating mechanism is demonstrated for yielding the interconnected hollow structure of PbO1.44 NAHSs. Remarkably, PbO1.44 NAHSs deliver stable capacities of 561 and 453 mA h g-1 after 100 and 200 cycles at 50 and 500 mA g-1, respectively, in sharp contrast to the performance of β-PbO2 MSs (52 and 43 mA h g-1). Structural and electrochemical measurements of the cycled electrodes indicate that the hollow and nanoarchitectural structure of PbO1.44 NAHSs enables their superior cycling and rate capabilities, benefiting from the effectively buffered volume expansion and shortened lithium storage distance, respectively. As such, this work highlights a robust PVP-assisted strategy to fabricate rare mixed-valence PbO1.44 NAHSs with outstanding electrochemical reactivity and mechanical robustness for lithium storage and various potential applications.