Fast‐Charging and High Volumetric Capacity Anode Based on Co₃O₄/CuO@TiO₂ Composites for Lithium‐Ion Batteries

Abstract

This paper presents an investigation of anodic TiO2 nanotube arrays (TNAs), with a Co3O4/CuO coating, for lithium‐ion batteries (LIBs). The coated TNAs are investigated using various analytical techniques, with the results clearly suggesting that the molar ratio of Co3O4/CuO in the TiO2 nanotubes substantially influences its battery performance. In particular, a cobalt/copper molar ratio of 2:1 on the TNAs (Co2Cu1@TNAs) features the best LIBs anode performance, exhibiting high reversible capacity and enhanced cycling stability. Noticeably, Co2Cu1@TNAs achieve excellent rate capability even after quite a high current density of 20.0 A g−1 (≈25 C, where C corresponds to complete discharge in 1 h) and superior volumetric reversible capacity of ≈3330 mA h−1 cm−3. This value is approximately seven times higher than those of a graphite‐based anode. This outstanding performance is attributed to the synergistic effects of Co2Cu1@TNAs: 1) the structural advantage of TNAs, with their large amount of free space to accommodate the large volume expansion during Li+ insertion/extraction and 2) the optimized ratio of Co3O4 and CuO in the composite for improved capacity. In addition, no binder or conductive agent is used, which is partly responsible for the overall improved volumetric capacity and electrochemical performance.

Electrochemical Performances of the Sn-Cu Alloy Negative Electrode Materials through Simple Chemical Reduction Method

“…The Sn-Cu alloy prepared at 60 o C (SC50@60) exhibited a volumetric capacity of 2,031 mAh/cc (on the basis of active materials) even after 50 cycles, which is 2.5 times that of the theoretical capacity of graphite. When the volumertic capacity is calculated based on the actual electrode, the volumetric capacity of SC50@60 electrode is 613 mAh/cc at initial cycle and 511 mAh/cc at 50th cycle which is higher than that of the practical graphite electrode (450 mAh/cc) [21]. As the charge and discharge progresses, the volume of the SC50 electrode also increases continuously.…”

In Situ Precipitation‐Induced Growth of Leaf‐like CuO Nanostructures on Cu–Ni Alloys for Binder‐Free Anodes in Li‐Ion Batteries

“…Electrochemical impedance spectroscopy (EIS) has been widely used to examine charge transfer, the properties of the SEI film, interfacial phenomena between the electrode and the electrolyte, and Li + diffusion kinetics in various electrode materials . Figure c shows the Nyquist plots of CuO‐350, CuO‐450, and CuO‐550 after 200 cycles at a current density of 0.5 A g −1 (≈0.74 C).…”

“…In the intermediate frequency, the second semicircle relates to the charge‐transfer resistance ( R ct ) of the active materials and double‐layer capacitance ( C dl ). The straight line at the low‐frequency range represents the Warburg impedance ( Z w ) of the Li + diffusion in the electrodes . The thermal oxide layer formed during the annealing process was completely removed with sandpaper to obtain reliable EIS results.…”

Challenges of Fast Charging for Electric Vehicles and the Role of Red Phosphorous as Anode Material: Review

“…Li 4 Ti 5 O 12 is recognized as a rapidly rechargeable anode material [84], but its specific capacity is not high (175 mAh g −1 ), and its lithium insertion potential is relatively high (1.55 V), so overall, the energy density of the full battery is limited. Other fast-charging anode materials are also developing, such as silicon oxide [85], titanium dioxide [86], nickel dioxide [87], and various transition metal oxides [88][89][90]. In particular, the Ti-Nb-O family, such as Ti 2 Nb 14 O 39 and TiNb 2 O 7 , are promising and possess good fast charging performance while offering 2D pathways for Li + transfer [91][92][93].…”