O-NiCo_(2)S_(4)/CNT复合材料对多硫化锂催化转化性能研究  

Catalytic conversion performance study of O-doped NiCo_(2)S_(4)/CNT composites for Li polysulfides

作　　者：沈李园 张桂鑫 马兆玲 SHEN Liyuan;ZHANG Guixin;MA Zhaoling(School of Chemistry and Pharmaceutical Sciences,Guangxi Normal University,Guilin 541004,Guangxi,China)

机构地区：[1]广西师范大学化学与药学学院,广西桂林541004

出　　处：《储能科学与技术》2023年第11期3318-3329,共12页Energy Storage Science and Technology

基　　金：国家自然科学基金项目(22002025),广西自然科学基金项目(2021GXNSFAA075040)。

摘　　要：NiCo_(2)S_(4)由于具有丰富的催化位点和金属特性,能够催化锂硫电池中的多硫化锂的氧化还原转化。然而,其催化活性和化学吸附性不足以抑制多硫化锂在长循环中的穿梭效应。通过水热法结合空气煅烧制备了氧掺杂NiCo_(2)S_(4)/CNT复合材料(O-NiCo_(2)S_(4)/CNT),系统的实验证明氧掺杂后体相NiCo_(2)S_(4)的结晶度增强,表面NiCo_(2)S_(4)趋于无定形态,O-NiCo_(2)S_(4)/CNT的电导率升高。其次,O掺杂可以有效调节NiCo_(2)S_(4)中金属阳离子的电子结构,增强催化活性位点的化学吸附和催化转化能力,进而提升多硫化锂的转化动力学,抑制多硫化锂的穿梭效应。基于O-NiCo_(2)S_(4)/CNT功能化隔膜的锂硫电池在0.2 C下初始放电容量高达1362.7 mAh/g,循环150圈后的容量为923 mAh/g,每圈的容量衰减率仅为0.21%。在3 C下,容量可达到701.8 mAh/g。本工作表明,氧原子掺杂金属硫化物是开发高效催化剂的一种有效策略。NiCo_(2)S_(4) can catalyze the redox conversion of polysulfides in Li-S batteries owing to its abundant catalytic sites and metallic nature.However,its catalytic activity and chemisorption properties are not sufficient for suppressing the shuttle effect of polysulfides during long cycles.The oxygen(O)-doped NiCo_(2)S_(4)/CNT(O-NiCo_(2)S_(4)/CNT)composite is synthesized using the hydrothermal method combined with annealing under air atmosphere,and systematical experiments demonstrate the increasing crystallinity,amorphous surface,and augmenting conductivity for O-NiCo_(2)S_(4)/CNT.Moreover,the O doping can effectively modulate the electronic structure of NiCo_(2)S_(4),thus improving the chemical absorption and catalytic conversion ability,promoting the conversion kinetics of polysulfides,and inhibiting its shuttle effect.The Li-S battery based on O-NiCo_(2)S_(4)/CNT functionalized separator has an initial high discharge capacity of 1362.7 mAh/g at 0.2 C and a capacity of 923 mAh/g after 150 cycles with a capacity decay rate of only 0.21%per cycle.The capacity can reach 701.8 mAh/g at 3 C.This work shows that oxygen atom doping of metal sulfides is an effective strategy for developing efficient catalysts.

关 键 词：氧掺杂 功能化隔膜 穿梭效应 多硫化锂 锂硫电池 

分 类 号：TM911[电气工程—电力电子与电力传动]