Ultrathin Layered Hydroxide Cobalt Acetate Nanoplates Face‐to‐Face Anchored to Graphene Nanosheets for High‐Efficiency Lithium Storage

Abstract

The dramatically increasing demand of high‐energy lithium‐ion batteries (LIBs) urgently requires advanced substitution for graphite‐based anodes. Herein, inspired from the extra capacity of lithium storage in solid‐electrolyte interface (SEI) films, layered hydroxide cobalt acetates (LHCA, Co(Ac)0.48(OH)1.52·0.55H2O) are introduced as novel and high‐efficiency anode materials. Furthermore, ultrathin LHCA nanoplates are face‐to‐face anchored on the surface of graphene nanosheets (GNS) through a facile solvothermal method to improve the electronic transport and avoid agglomeration during repeated cycles. Profiting from the parallel structure, LHCA//GNS nanosheets exhibit extraordinary long‐term and high‐rate performance. At the current densities of 1000 and 4000 mA g−1, the reversible capacities maintain ≈1050 mAh g−1 after 200 cycles and ≈780 mAh g−1 after 300 cycles, respectively, much higher than the theoretical value of LHCA according to the conversion mechanism. Fourier transform infrared spectroscopy confirms the conversion from acetate to acetaldehyde after lithiation. A reasonable mechanism is proposed to elucidate the lithium storage behaviors referring to the electrocatalytic conversion of OH groups with Co nanocatalysts. This work can help further understand the contribution of SEI components (especially LiOH and LiAc) to lithium storage. It is envisaged that layered transition metal hydroxides can be used as advanced materials for energy storage devices.

Interfacial Phenomena/Capacities Beyond Conversion Reaction Occurring in Nano‐sized Transition‐Metal‐Oxide‐Based Negative Electrodes in Lithium‐Ion Batteries: A Review

“…The metallic Co nanoparticles serve as electrocatalyst for further reaction of LiOH and LiAc with Li resulting in Li 2 O/LiH and acetaldehyde, respectively. The conversion from acetate to acetaldehyde was confirmed with FT‐IR . The reaction of LiOH with Li leading to Li 2 O/LiH catalyzed by metallic Ru, confirmed through solid state NMR and theoretical calculations was also reported by Hu et al …”

Mn3O4@NC Composite Nanorods as a Cathode for Rechargeable Aqueous Zn‐Ion Batteries

“…At a current density of 500 mA g À 1 , the curve of the capacitance retention is shown in Figure 6d. [44,47,48] The reasonable explanations can be ascribed to two aspects: (1) the reversible reactions and low electrochemical activities of active materials are caused by the infiltration of the electrolyte to the cathode, and (2) the synergistic effect of Zn 2 + and Mn 2 + and the redox reaction effect of Mn 2 + exist in electrolyte, which restrain the structural collapse and aggregation of active materials and diminish the generation of other impurities reducing the performances of ZIBs. After 500 cycles, the capacity of the electrode exhibits a slight decrease, and it retains a higher capacity of 180 mAh g À 1 at the end of 500 cycles.…”

2 D Materials for Electrochemical Energy Storage: Design, Preparation, and Application

“…Su et al. anchored layered hydroxide cobalt acetates on the surface of graphene nanosheets (LHCA//GNS) through a facile solvothermal method . Benefiting from the parallel structure, LHCA//GNS exhibited extraordinary long‐term and high‐rate performance with a reversible capacity of 1050 mAh g −1 after 200 cycles at 1 A g −1 .…”