Nanoscale Wrinkled Cu as a Current Collector for High-Loading Graphite Anode in Solid-State Lithium Batteries

Abstract

Solid-state lithium batteries have been intensively studied as part of research activities to develop energy storage systems with high safety and stability characteristics. Despite the advantages of solid-state lithium batteries, their application is currently limited by poor reversible capacity arising from their high resistance. In this study, we significantly improve the reversible capacity of solid-state lithium batteries by lowering the resistance through the introduction of a graphene and wrinkle structure on the surface of the copper (Cu) current collector. This is achieved through a process of chemical vapor deposition (CVD) facilitating graphene-growth synthesis. The modified graphene/wrinkled Cu current collector exhibits a periodic wrinkled pattern 420 nm in width and 22 nm in depth, and we apply it to a graphite composite electrode to obtain an improved areal loading average value of ∼2.5 mg cm–2. The surface-modified Cu current collector is associated with a significant increase in discharge capacity of 347 mAh g–1 at 0.2 C when used with a solid polymer electrolyte. Peel test results show that the observed enhancement is due to the improved strength of adhesion occurring between the graphite composite anode and the Cu current collector, which is attributed to mechanical interlocking. The surface-modified Cu current collector structure effectively reduces resistance by improving adhesion, which subsequently improves the performance of the solid-state lithium batteries. Our study can provide perspective and emphasize the importance of electrode design in achieving enhancements in battery performance.

High Facets on Nanowrinkled Cu via Chemical Vapor Deposition Graphene Growth for Efficient CO2 Reduction into Ethanol

“…Under our new approach, we used the Cu film generated after CVD graphene growth as an electrocatalyst. From the viewpoint of the Cu structure and morphology, after the graphene layer forms on the Cu film by nucleation of a carbon source generated from methane, the thermal expansion energy difference between Cu and graphene results in both expansion and compression of the Cu top surface during the cooling process. − This leads to the formation of a periodic hill-and-valley wrinkle morphology.…”

Insights on the work function of the current collector surface in anode-free lithium metal batteries

“…A high index surface facet structure was obtained by forming nano-wrinkle structures on the bCu. 23,24 At an elevated temperature of 1000 C, a graphene layer was formed on the bCu by owing CH 4 gas. During the cooling process, the copper current collector with high index surface facets (hCu) evolves due to the mismatch in thermal expansion between the graphene and copper surface.…”

Rational Engineering of Anode Current Collector for Dendrite-Free Lithium Deposition: Strategy, Application, and Perspective

“…However, ASSB exhibits high anode/electrolyte interfacial resistance, the uneven distribution of interfacial current accelerates the dendrite growth, and anode current collector engineering is an efficient approach to solve these problems. Wu M. et al (2021 ) introduced a graphene and periodic wrinkled structure on the surface of Cu by CVD to improve adhesion, reduce interfacial resistance, and improve the reversibility. Au- or Ni-coated current collectors with microsized pores, which facilitate uniform current distribution, were reported to deposit Li in the engineered pores and obtain stable lithium plating/stripping in ASSB ( Shinzo et al, 2020 ).…”