镍钴水滑石纳米笼/GO复合材料在锂离子电池负极中的应用

Application of nickel-cobalt hydrotalc nanocage/GO composite in the anode of lithium-ion batteries

近年来,水滑石(LDH)材料因其组成、结构和形貌易于调节,具有丰富的活性位点,被认为是高性能锂离子电池(LIBs)负极的替代材料,然而水滑石作为负极仍存在电导率差和结构易聚集等问题.于此同时,金属有机框架(MOFs)及碳基材料也由于其优秀的孔隙率、比表面积以及良好的电导率在储能领域得到了广泛的关注.考虑到这二者有望对LDH的主要缺陷有所改进,提出了将原位沉淀、化学刻蚀法和静电吸附法相结合,使镍钴水滑石纳米笼(H-(Ni,Co)-LDHP)能够固定在GO上,从而得到镍钴水滑石纳米笼/氧化石墨烯复合材料(H-(Ni,Co)-LDHP/GO).这种GO上密集分布的中空纳米结构更能有效抑制水滑石纳米片的聚集,并有利于锂离子的脱嵌.H-(Ni,Co)-LDHP/GO纳米复合材料作为锂离子电池的负极,在电流密度为50m A·g^(-1)下,循环第一圈库伦效率可达68%,循环50圈后电容保留率为68.4%.

In recent years,layered double hydroxide(s LDH)material is considered to be an alternative material of high performance lithium ion battery(LIBs)because of its adjustable composition,structure and morphology.However,LDH as a negative pole still has problems such as poor conductivity and easy structure aggregation.At the same time,metal-organic frameworks(MOFs)and carbon-based materials have also attracted wide attention in the field of energy storage due to their excellent porosity,specific surface area and good conductivity.Considering the main defects of LDH,presents a combination of in situ precipitation,chemical etching and electrostatic adsorption method,so that hollowed Ni-Co layered double hydroxide polyhedron(H-(Ni,Co)-LDHP)can be fixed on GO,resulting in hollowed Ni-Co layered double hydroxide polyhedron/graphene oxide composite(H-(Ni,Co)-LDHP/GO).This densely distributed hollow nanostructure on GO can more effectively inhibit the aggregation of hydrotalc nanosheets and facilitate the unembedding of lithium ions.H-(Ni,Co)-LDHP/GO nanocomposite,as the negative electrode of lithium-ion battery,achieves the first cycle efficiency of 68% at the current density of 50 mA·g^(-1),and the capacitorretention rate after 50 cycles is 68.4%.