TY - JOUR
T1 - Hierarchical hollow microspheres grafted with Co nanoparticle-embedded bamboo-like N-doped carbon nanotube bundles as ultrahigh rate and long-life cathodes for rechargeable lithium-oxygen batteries
AU - Kim, Jung Hyun
AU - Park, Seung Keun
AU - Oh, Yeon Jong
AU - Kang, Yun Chan
N1 - Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2017R1A2B2008592 ).
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018/2/15
Y1 - 2018/2/15
N2 - Rational design of efficient, affordable, and durable electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is essential for rechargeable lithium-oxygen (Li–O2) batteries. We present for the first time hierarchical hollow microspheres grafted with metallic Co-embedded bamboo-like N-doped carbon nanotube bundles (Co-b-NCNTs hollow microspheres) as oxygen electrodes for Li-air batteries. Hierarchical composite microspheres are prepared via a facile two-step process involving synthesis of Co3O4-MgO hollow microspheres by spray pyrolysis, followed by internal and external growth of bamboo-like NCNTs in the shells. During post-treatment, metallic Co and MgO nanoparticles play key respective roles in catalyzing in-situ growth of NCNTs and maintaining structural integrity of the composites. The hierarchical composite structure with Co and N doping not only provides ample active sites for the OER and ORR, but also sufficient space for storing produced Li2O2. Thus, Co-b-NCNTs hollow microspheres exhibit high initial round-trip efficiency, long-term cycling and ultrahigh rate performances when applied as oxygen electrodes for Li–O2 batteries. The initial discharge capacity and round-trip efficiency at a current density of 200 mA g−1 are 28,968 mA h g−1 and 78.2%, respectively. Specific capacities at cutoff capacities of 500 and 1000 mA h g−1 are stable for 201 and 157 cycles, respectively.
AB - Rational design of efficient, affordable, and durable electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is essential for rechargeable lithium-oxygen (Li–O2) batteries. We present for the first time hierarchical hollow microspheres grafted with metallic Co-embedded bamboo-like N-doped carbon nanotube bundles (Co-b-NCNTs hollow microspheres) as oxygen electrodes for Li-air batteries. Hierarchical composite microspheres are prepared via a facile two-step process involving synthesis of Co3O4-MgO hollow microspheres by spray pyrolysis, followed by internal and external growth of bamboo-like NCNTs in the shells. During post-treatment, metallic Co and MgO nanoparticles play key respective roles in catalyzing in-situ growth of NCNTs and maintaining structural integrity of the composites. The hierarchical composite structure with Co and N doping not only provides ample active sites for the OER and ORR, but also sufficient space for storing produced Li2O2. Thus, Co-b-NCNTs hollow microspheres exhibit high initial round-trip efficiency, long-term cycling and ultrahigh rate performances when applied as oxygen electrodes for Li–O2 batteries. The initial discharge capacity and round-trip efficiency at a current density of 200 mA g−1 are 28,968 mA h g−1 and 78.2%, respectively. Specific capacities at cutoff capacities of 500 and 1000 mA h g−1 are stable for 201 and 157 cycles, respectively.
KW - Carbon nanotubes
KW - Cathode material
KW - Hierarchical structure
KW - Li-O batteries
KW - Nanostructured material
KW - Spray pyrolysis
UR - http://www.scopus.com/inward/record.url?scp=85037358832&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2017.12.018
DO - 10.1016/j.cej.2017.12.018
M3 - Article
AN - SCOPUS:85037358832
VL - 334
SP - 2500
EP - 2510
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
SN - 1385-8947
ER -