Strongly coupled Te-SnS2/MXene superstructure with self-autoadjustable function for fast and stable potassium ion storage

Potassium-ion batteries (PIBs) are a promising candidate for next-generation electric energy storage applications because of the abundance and low cost of potassium. However, the development of PIBs is limited by sluggish kinetics and huge volume expansion of anodes, leading to poor rate capability and cycling stability. Herein, an advanced superstructure anode, including Te-doped SnS2 nanosheets uniformly anchored on MXene surface (Te-SnS2/MXene), is rationally designed for the first time to boost K+ storage performance. Featuring with strong interface interaction and self-autoadjustable interlayer spacings, the Te-SnS2/MXene can efficiently accelerate electron/ion transfer, accommodate volume expansion, inhibit crack formation, and improve pseudocapacitive contribution during cycling. Thus, the novel Te-SnS2/MXene anode delivers a high reversible capacity (343.2 mAh g(-1) after 50 cycles at 0.2 A g(-1)), outstanding rate capability (186.4 mAh g(-1) at 20 A g(-1)), long cycle stability (165.8 mAh g(-1) after 5000 cycles at 10 A g(-1) with a low electrode swelling rate of only 15.4%), and reliable operation in flexible full battery. The present Te-SnS2/MXene becomes among the best transition metal-based anode materials for PIBs reported to date. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

An advanced superstructure anode Te-SnS2/MXene is designed to enhance the potassium-ion storage performance, featuring strong interface interaction and self-autoadjustable interlayer spacings.