摘要
Bi2Te3钾离子电池负极存在结构不稳定性和电化学反应动力学缓慢问题.本研究在手风琴状MXene基底上生长棒状Bi2Te3,随后利用P掺杂制备了高性能P-Bi2Te3/MXene超结构.这种新型负极具有丰富的Te空位和良好的自适应特性,展现出优异的循环稳定性(在0.2 A∙g-1电流密度下200次循环后可逆容量为323.1 mAh∙g-1)和出色的倍率能力(20 A∙g-1时可逆容量为67.1 mAh∙g-1).动力学分析和非原位表征表明,该超结构具有优异的赝电容特性、出色的K+离子扩散能力以及可逆的嵌入反应和转化反应机理.
Abstract
With increasing global energy demand and stricter environmental protection requirements,energy storage technology has become a research hotspot in the global energy field.New types of energy storage devices continue to emerge owing to the continuous development of cost-effective energy storage technology.Among them,potassium-ion batteries have received widespread attention as a new type of alkali metal ion battery because of their high capacity and low cost and are considered one of the future development directions.However,the research on potassium-ion batteries is still in its infancy,with many challenges to overcome regarding practical applications.A key factor affecting the performance of potassium-ion batteries is the anode material,as it not only affects the manufacturing costs but also directly affects the power density and energy density of the battery.Traditional anode materials for lithium-ion batteries cannot meet the requirements of potassium-ion batteries.Therefore,developing high-performance anode materials suitable for potassium-ion batteries is an important research direction at present.The charge and discharge rate and cycling life of potassium-ion batteries also need further improvements.Currently,the low-rate performance,short cycle life,and unsatisfactory practical capacities limit their practical application and commercialization.However,the future of potassium-ion batteries remains promising.Upon resolving the aforementioned issues,potassium-ion batteries will have diverse application prospects,such as electric vehicles,energy storage stations,and smart grids,providing important support for solving energy problems.Therefore,the research and development of potassium-ion batteries are an important direction in the global energy field.Current research efforts are primarily focused on exploring novel anode materials with exceptional ratability and cyclability.In this regard,we synthesized a new type of anode material based on bismuth telluride(Bi2Te3)and experimentally studied its applicability in potassium-ion batteries.The performance of Bi2Te3 anode for potassium-ion batteries has been limited by its structural instability and slow electrochemical reaction kinetics.In this study,rod-like Bi2Te3 was grown on accordion-like MXene,followed by P-doping to obtain a high-performance P-Bi2Te3/MXene superstructure.This novel anode had abundant Te vacancies and good self-auto adjustable function,providing excellent cycling stability(323.1 mAh·g-1 after 200 cycles at 0.2 A·g-1)and outstanding rate capability(67.1 mAh·g-1 at 20 A·g-1).Kinetic analysis and ex situ characterization indicate that the superstructure exhibits superior pseudocapacitive properties,high electrical conductivity,favorable diffusion capability,and reversible insertion and conversion reaction mechanism.
基金项目
国家自然科学基金(22005223)
国家自然科学基金(21975187)
广东省基础与应用基础研究基金(2019A1515012161)
五邑大学青年科研基金(2019Td01)
五邑大学高层次人才科研启动项目(2018RC50)
五邑大学港澳联合研发基金(2019WGALH10)
万方数据