Dual‐Carbon Confined SnP<sub>2</sub>O<sub>7</sub> with Enhanced Pseudocapacitances for Improved Li/Na‐Ion Batteries
Xinzhu Guo, Zhengwei Wan, Di Wei, Xiaomin Zeng, Zeheng Li, Wei Jiang, Hongxun Wang, Min Ling, Hui Li, Chengdu Liang
Abstract
Abstract Tin‐based materials have obtained much attention in lithium‐ion batteries (LIBs) due to high specific capacity. However, the large volume change and poor electroconductivity hinder their further practical application. Herein, a C 18 N 12 (CN)‐wired amorphous carbon coated pyrophosphate tin (SnP 2 O 7 @C) ultrafine nanoparticles composite (SnP 2 O 7 @C/CN) is prepared by solvothermal‐calcination with phytic acid (PA) as phosphorus and carbon sources simultaneously. Ultrafine‐nanocrystallization and dual‐carbon doping enhances the pseudocapacitance of SnP 2 O 7 @C/CN and thus, exhibit good electrochemical performance and high lithium/sodium storage efficiency. As anode of LIBs, the SnP 2 O 7 @C/CN exhibits a superior reversible capacity of 557.3 mAh/g after 100 cycles at a current density of 0.2 A/g and a conspicuous cyclability of 352.3 mAh/g after 800 cycles at 1 A/g. For sodium‐ion batteries (SIBs), the stable discharge capacity of SnP 2 O 7 @C/CN electrode is 91.5 mAh/g after 800 cycles at a high current density of 2 A/g. This strategy can increase active sites, provide large electrolyte/electrode contact area, and improve electroconductivity. Moreover, SnP 2 O 7 @C/CN electrode provides a buffer space for structural strains caused by volume changes during charging and discharging.