Potassium ion batteries(PIBs)are emerging as potential next-generation energy storage systems on account of their low cost and high theoretical energy density.Nevertheless,they also face challenges of low specific cap...Potassium ion batteries(PIBs)are emerging as potential next-generation energy storage systems on account of their low cost and high theoretical energy density.Nevertheless,they also face challenges of low specific capacity and suboptimal cycling stability.Herein,we synthesize a cocoon-like P3-type K_(0.5)Mn_(0.7)Ni_(0.3)O_(2)(KMNO)cathode material by a self-template method.The KMNO cocoons possess a hierarchical layered architecture composed of nanoparticle stacking,which can accelerate the transport kinetics of potassium ions,mitigate the stress caused by K^(+)intercalation and deintercalation,and improve structural stability.In addition,Ni can not only alleviate the Jahn-Teller distortion and suppress the phase transition to stabilize the structure,but also act as an electrochemically active element,providing the capacity of two electrons from Ni2+to Ni4+.Combining the advantages of structure and nickel substitution,the P3-type KMNO cocoons are used for electrochemical performance testing of PIB cathodes,delivering an excellent rate capability of 57.1 m A h g^(-1)at 500 m A g^(-1)and a remarkable cycling stability of 77.0%over 300 cycles at 100 m A g^(-1).Impressively,the KMNO cocoons//pitch-derived soft carbon assembled full battery exhibits superior electrochemical performance with a reversible capacity of 79.7 m A h g^(-1)at 50 m A g^(-1).Moreover,ex-situ XRD also further reveals a solid solution phase reaction with a volume change of only 1.46%.This work furnishes a suitable approach to fabricating highperformance layered oxide cathodes for PIBs with outstanding cycling stability and rate capability.展开更多
Potassium-ion batteries(PIBs) as a substitute for lithium-ion batteries have aroused widespread attention and have been rapidly developed. In the positive electrode materials, polyanionic compound has a high working v...Potassium-ion batteries(PIBs) as a substitute for lithium-ion batteries have aroused widespread attention and have been rapidly developed. In the positive electrode materials, polyanionic compound has a high working voltage and large reversible capacity on account of its distinct framework and the strong inducing effect of the anionic group. Herein, a KVPO_(4)F/reduced graphene oxide(KVPF/r GO) hybrid was fabricated via a simple multi-step approach as the polyanionic cathode material for PIBs. Profiting from the small size of KVPF nanoparticles and their uniform distribution in the r GO framework, the assynthesized KVPF/r GO hybrid manifests a large discharge capacity of 103.2 mAh g^(-1) with an outstanding energy density of 436.5 Wh kg^(-1). Through r GO decoration, the hybrid also demonstrates remarkable rate and cycling properties. By employing ex-situ X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) techniques, the potassium storage mechanism of KVPF was clearly revealed. The facile preparation procedure and superior properties endow it great application prospects in large-scale energy storage.展开更多
由于其高容量和丰富的资源,过渡金属硫化物(TMS)已被证明是钾离子电池具有吸引力的负极材料之一.然而,TMS通常受到导电性差和体积膨胀大的限制,可能导致结构不稳定和电池循环性能差.本工作通过将超小Cu_(2)S纳米粒子植入碳纳米线(Cu_(2)...由于其高容量和丰富的资源,过渡金属硫化物(TMS)已被证明是钾离子电池具有吸引力的负极材料之一.然而,TMS通常受到导电性差和体积膨胀大的限制,可能导致结构不稳定和电池循环性能差.本工作通过将超小Cu_(2)S纳米粒子植入碳纳米线(Cu_(2)S@C NWs),显著减轻了纳米粒子聚集和有害的结构退化.与传统的Cu_(2)S颗粒相比,每根纳米线的体积变化都得到了有效调节,这极大地改善了形态完整性,从而显著提高了循环寿命.正如预期的那样,Cu_(2)S@C NW负极可提供391.1 mA h g^(-1)的大可逆容量,在5 A g^(-1)时具有118.1 mA h g^(-1)的出色倍率性能,以及在2 A g^(-1)下经过500次循环后77.2%的高容量保持率.此外,当Cu_(2)S@C NW负极与KVP04F/CNTs正极组装形成钾离子全电池时,在50 mA g^(-1)下循环100次后显示出110.8 mA h g^(-1)的良好放电容量.这种纳米颗粒阻聚策略拓宽了纳米工程的视野,以释放嵌脱钾引起的应力,并促进钾离子电池高效负极的进一步发展.展开更多
基金supported by the National Natural Science Foundation of China(22179063)。
文摘Potassium ion batteries(PIBs)are emerging as potential next-generation energy storage systems on account of their low cost and high theoretical energy density.Nevertheless,they also face challenges of low specific capacity and suboptimal cycling stability.Herein,we synthesize a cocoon-like P3-type K_(0.5)Mn_(0.7)Ni_(0.3)O_(2)(KMNO)cathode material by a self-template method.The KMNO cocoons possess a hierarchical layered architecture composed of nanoparticle stacking,which can accelerate the transport kinetics of potassium ions,mitigate the stress caused by K^(+)intercalation and deintercalation,and improve structural stability.In addition,Ni can not only alleviate the Jahn-Teller distortion and suppress the phase transition to stabilize the structure,but also act as an electrochemically active element,providing the capacity of two electrons from Ni2+to Ni4+.Combining the advantages of structure and nickel substitution,the P3-type KMNO cocoons are used for electrochemical performance testing of PIB cathodes,delivering an excellent rate capability of 57.1 m A h g^(-1)at 500 m A g^(-1)and a remarkable cycling stability of 77.0%over 300 cycles at 100 m A g^(-1).Impressively,the KMNO cocoons//pitch-derived soft carbon assembled full battery exhibits superior electrochemical performance with a reversible capacity of 79.7 m A h g^(-1)at 50 m A g^(-1).Moreover,ex-situ XRD also further reveals a solid solution phase reaction with a volume change of only 1.46%.This work furnishes a suitable approach to fabricating highperformance layered oxide cathodes for PIBs with outstanding cycling stability and rate capability.
基金supported by the National Natural Science Foundation of China (22179063)。
文摘Potassium-ion batteries(PIBs) as a substitute for lithium-ion batteries have aroused widespread attention and have been rapidly developed. In the positive electrode materials, polyanionic compound has a high working voltage and large reversible capacity on account of its distinct framework and the strong inducing effect of the anionic group. Herein, a KVPO_(4)F/reduced graphene oxide(KVPF/r GO) hybrid was fabricated via a simple multi-step approach as the polyanionic cathode material for PIBs. Profiting from the small size of KVPF nanoparticles and their uniform distribution in the r GO framework, the assynthesized KVPF/r GO hybrid manifests a large discharge capacity of 103.2 mAh g^(-1) with an outstanding energy density of 436.5 Wh kg^(-1). Through r GO decoration, the hybrid also demonstrates remarkable rate and cycling properties. By employing ex-situ X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) techniques, the potassium storage mechanism of KVPF was clearly revealed. The facile preparation procedure and superior properties endow it great application prospects in large-scale energy storage.
基金financially supported by the National Natural Science Foundation of China(22179063)。
文摘由于其高容量和丰富的资源,过渡金属硫化物(TMS)已被证明是钾离子电池具有吸引力的负极材料之一.然而,TMS通常受到导电性差和体积膨胀大的限制,可能导致结构不稳定和电池循环性能差.本工作通过将超小Cu_(2)S纳米粒子植入碳纳米线(Cu_(2)S@C NWs),显著减轻了纳米粒子聚集和有害的结构退化.与传统的Cu_(2)S颗粒相比,每根纳米线的体积变化都得到了有效调节,这极大地改善了形态完整性,从而显著提高了循环寿命.正如预期的那样,Cu_(2)S@C NW负极可提供391.1 mA h g^(-1)的大可逆容量,在5 A g^(-1)时具有118.1 mA h g^(-1)的出色倍率性能,以及在2 A g^(-1)下经过500次循环后77.2%的高容量保持率.此外,当Cu_(2)S@C NW负极与KVP04F/CNTs正极组装形成钾离子全电池时,在50 mA g^(-1)下循环100次后显示出110.8 mA h g^(-1)的良好放电容量.这种纳米颗粒阻聚策略拓宽了纳米工程的视野,以释放嵌脱钾引起的应力,并促进钾离子电池高效负极的进一步发展.
