Ultra‐Fast Cycling of Nanoscale Thin‐Film LiCoO₂ Electrodes in Aqueous Electrolytes

Abstract

Additive‐free nanoscale LiCoO2 thin‐films deposited on Si substrates using DC sputtering show exceptional electrochemical performance due to the unique kinetics of the nanoscale thin‐film in aqueous environment. At extremely high scan rates and galvanostatic current densities of up to 100 mV s−1 and 200 C respectively, a capacity retention equivalent to 97 mAh g−1 (4.8 μAh cm−2, 48.3 μAh cm−2 μm−1) is obtained. A significant contribution of non‐diffusion controlled kinetics in a LiCoO2 electrode is shown.

High‐Rate Lithium‐Ion Cycling in Electrodeposited Binder‐Free Thin‐Film Vanadium Oxide Cathodes with Lithium Metal Anodes in Ionic Liquid and Polymer Gel Analogue Electrolytes

“…The electrical conductivity for a V 2 O 5 film of similar dimensions (∼260 nm) film [28] is 1.17×10 −3 S cm −1 which is in the same region if not better than typical oxide materials used as cathodes for lithium ion batteries. The average lithium ion diffusion coefficient calculated for the crystalline V 2 O 5 was determined to be 7.83×10 −10 cm 2 s −1 for the 220 nm films which also compares very favourably with oxide materials typically utilised [29] . The diffusion coefficients obtained for the α/ϵ and ϵ/δ phases of the film are 8.53×10 −10 and 7.14×10 −10 cm 2 s −1 , respectively.…”

“…The average lithium ion Batteries & Supercaps diffusion coefficient calculated for the crystalline V 2 O 5 was determined to be 7.83 × 10 À 10 cm 2 s À 1 for the 220 nm films which also compares very favourably with oxide materials typically utilised. [29] The diffusion coefficients obtained for the α/ɛ and ɛ/δ phases of the film are 8.53 × 10 À 10 and 7.14 × 10 À 10 cm 2 s À 1 , respectively. The sharp peaks in the voltammograms recorded at relatively high rates (0.5 mV s À 1 over 600 mV) which approximates to a 3 C-rate also indicates the material is not complicated by low electronic conductivity.…”

“…(5)] where k 1 is equal to the slope and k 2 is equal to the intercept when is plotted against . The percentage contribution of diffusion and non‐diffusion controlled kinetics is calculated using Equations (6) and (7), respectively [29,32] …”

“…The percentage contribution of diffusion and non-diffusion controlled kinetics is calculated using Equations (6) and (7), respectively. [29,32] i…”

Advanced Electrochemical Analysis for Energy Storage Interfaces

“…By adding specific redox mediators as probes, the interfacial properties of energy storage systems can be analyzed. CV has been used to understand and characterize the solid-electrolyte interphase (SEI) related surface deposition processes − and interfacial activities, − as well as electron, ion, and molecule transport properties across interfaces. − …”