SnP entangled by carbon nanotube networks as anode for pseudocapacitive half/full battery

Abstract

Due to the lower operating voltage and higher theoretical specific capacity, tin phosphide is considered a class of materials with prospects as an anode material for lithium-ion batteries (LIBs). Among them, tin monophosphide has attracted people's attention due to its unique layered structure. Unfortunately, because of the challenging synthesis method and metastable nature, the application of SnP is limited. In this work, tin phosphide/carbon nanotubes (SnP/CNTs) are prepared by controlling the nucleation and adjusting the ratio of phosphorus/carbon using carbon nanotube as initiator. Sn-MOF is used as a template to make the morphology of SnP more evenly, and carbon nanotubes can also be used as a conductive network to increase the speed of electron transmission. As an anode material for LIBs, SnP/CNTs reveals superior rate performances (reversible capability of 610 mA·h·g−1 at 2 000 mA·g−1). The full-cell was assembled and tested, after 50 cycles at 0.1 C, the capacity can maintain 292 mA·h·g−1, and its capacity retention rate can reach 80.5%. After 230 cycles, its capacity can maintain at around 223 mA·h·g−1. In addition, SnP/CNTs materials exhibit 89% pseudocapacitance contribution upon cycling, which indicates the robust Li+ storage and satisfactory fast-charging capability. Hence, SnP/CNTs suggests a promising anode material for energy storage system.