将Cu_(2)S超细纳米粒子均匀植入碳纳米线以实现高效钾离子电池负极

Uniform implantation of ultrafine Cu_(2)S nanoparticles into carbon nanowires for efficient potassium-ion battery anodes

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.

Owing to their high capacities and abundant resources,transition metal sulfides(TMSs)have been proven attractive anode materials for potassium-ion(K-ion)batteries.Nevertheless,TMSs are usually limited by poor electrical conductivity and large volume expansion,leading to structural instability and inferior battery cyclability.Herein,we significantly alleviated the nanoparticle aggregation and pernicious structural degradation by embedding ultrasmall Cu_(2)S nanoparticles in carbon nanowires(Cu_(2)S@C NWs).The volume change in every NW was effectively accommodated compared with conventional Cu_(2)S particles,dramatically improving morphological integrity and leading to a noticeable enhancement in cycle life.As expected,the Cu_(2)S@CNWanode can deliver a large reversible capacity of 391.1 mA h g^(−1),an excellent rate capability of 118.1 mA h g^(−1)at 5 A g^(−1),and a high-capacity retention of 77.2%after 500 cycles at 2 A g^(−1).In addition,when the Cu_(2)S@CNWanode was assembled with the KVPO4F/carbon nanotubes(CNTs)cathode to form a K-ion full cell,it showed a good discharge capacity of 110.8 mA h g^(−1)after 100 cycles at 50 mA g^(−1).This nanoparticle agglomeration-retardant strategy broadens the horizons for nanoengineering to release the stress induced by potassium(de)intercalation and facilitate the further development of efficient anodes for K-ion batteries.