Additive-Free Hollow-Structured Co3O4 Nanoparticle Li-Ion Battery: The Origins of Irreversible Capacity Loss

• Published in: ACS nano 2014-07, Vol.8 (7), p.6701-6712
• Main Authors: Kim, Youngjun, Lee, Jung-Hyun, Cho, Sungeun, Kwon, Yongwoo, In, Insik, Lee, Jihoon, You, Nam-Ho, Reichmanis, Elsa, Ko, Hyungduk, Lee, Kyu-Tae, Kwon, Hyun-Keun, Ko, Doo-Hyun, Yang, Heesun, Park, Byoungnam
• Format: Article
• Language: English
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/nn500218m

Origins of the irreversible capacity loss were addressed through probing changes in the electronic and structural properties of hollow-structured Co3O4 nanoparticles (NPs) during lithiation and delithiation using electrochemical Co3O4 transistor devices that function as a Co3O4 Li-ion battery. Additive-free Co3O4 NPs were assembled into a Li-ion battery, allowing us to isolate and explore the effects of the Co and Li2O formation/decomposition conversion reactions on the electrical and structural degradation within Co3O4 NP films. NP films ranging between a single monolayer and multilayered film hundreds of nanometers thick prepared with blade-coating and electrophoretic deposition methods, respectively, were embedded in the transistor devices for in situ conduction measurements as a function of battery cycles. During battery operation, the electronic and structural properties of Co3O4 NP films in the bulk, Co3O4/electrolyte, and Co3O4/current collector interfaces were spatially mapped to address the origin of the initial irreversible capacity loss from the first lithiation process. Further, change in carrier injection/extraction between the current collector and the Co3O4 NPs was explored using a modified electrochemical transistor device with multiple voltage probes along the electrical channel.