Effect of Electrode Dimensionality and Morphology on the Performance of Cu₂Sb Thin Film Electrodes for Lithium‐Ion Batteries

Abstract

Keywords: Electrochemistry / Thin films / Copper / Antimony / Intermetallic phases Although graphitic carbons have been commercially used in lithium-ion batteries for many years, their low crystallographic density limits their use in applications where space is at a premium. Among the alternative anode materials being considered for these applications are Zintl phases and intermetallic insertion anodes. Historically, main-group-metalbased anode materials have had problems with respect to volume expansion experienced on lithiation and its effect on cycle life. In this paper, we report the role of morphology and electrode dimensionality in extending the cycle life of the

Exploring the Role of Vinylene Carbonate in the Passivation and Capacity Retention of Cu2Sb Thin Film Anodes

“…If Cu diffuses away from electrode, some of the conductive Cu network that allows for good electronic conductivity in the lithiated Sb phases may no longer be present and could result in some loss of active material conductivity and cause the observed capacity fade in addition to the delamination that has been observed for Cu 2 Sb cycled without VC. 81 However, this is not consistent with previous observations from our group in which Cu-deficient Cu 2 Sb showed good reversibility and cycling stability. 73 Second, it is possible that the Cu species in the SEI formed without VC could be reacting with the SEI and electrolyte components, which could be another explanation for why the HPR and MPR SEI samples without VC did not contain carbonate binding environments.…”

“…First, the observed Cu diffusion could be playing a role in a short lifetime and rapid capacity fade of the Cu 2 Sb thin film cycled without VC. If Cu diffuses away from electrode, some of the conductive Cu network that allows for good electronic conductivity in the lithiated Sb phases may no longer be present and could result in some loss of active material conductivity and cause the observed capacity fade in addition to the delamination that has been observed for Cu 2 Sb cycled without VC . However, this is not consistent with previous observations from our group in which Cu-deficient Cu 2 Sb showed good reversibility and cycling stability .…”

Cover Picture: Hydroformylation in the Realm of Scents (ChemCatChem 2/2014)

“…To better control this critical variable, the addition of SEI formers, such as vinyl carbonate (VC), to the electrolyte is commonly used to introduce desired SEI film properties 18. For lithium‐based cells, some studies have been done with artificial SEI formers; however, the metal‐surface reactivity and large volume changes are detrimental to many proposed systems 11. 19 Building on our earlier study of lithium‐surface‐bound trialkyl silane groups, we have used these surface‐bound groups as a point of surface attachment to build functionality onto the surface of the anode that could act as an anchor for a more robust barrier to solvent diffusion 14.…”

“…Notable examples of inorganic coatings include the addition of AlI 3 to the electrolyte to form a mixture of LiI and the lithiated Zintl phase LiAl on the anode surface, which was shown to improve lithium cycling versus standard cells 9. 10 However, upon cycling, issues with dimensional stability were observed as Zintl phases, although excellent lithium‐ion conductors, tend to be very brittle, and the large volume changes cause cracking and loss of surface contacts, which is detrimental to long‐term cycling 11…”

The energy-storage frontier: Lithium-ion batteries and beyond

“…These fi lms are electronically insulating in nature, which increases the impedance of the electrodes, leading to a loss of usable energy over time. 74 Electrolyte reduction onto graphite anodes occurs in the same manner as for silicon anodes, but the resulting organic layer forms primarily on the fi rst cycle and is stable, conducting Li ions from the electrolyte to the graphite anode, which intercalates them into its existing structure with little volume change. Research aimed at stabilizing silicon-anode surfaces through tailored, often fl uorinated electrolyte components that improve the properties of the reduced organic layer on silicon surfaces is ongoing.…”