Electrophoretic Deposition of Binder‐Free MnO₂/Graphene Films for Lithium‐Ion Batteries

Abstract

Binder‐free, nano‐sized needlelike MnO2‐submillimeter‐sized reduced graphene oxide (nMnO2‐srGO) hybrid films with abundant porous structures were fabricated through electrophoretic deposition and subsequent thermal annealing at 500 °C for 2 h. The as‐prepared hybrid films exhibit a unique hierarchical morphology, in which nMnO2 with a diameter of 20—50 nm and a length of 300—500 nm is randomly anchored on both sides of srGO. When evaluated as binder‐free anodes for lithium‐ion half‐cell, the nMnO2‐srGO composites with a content of 76.9 wt% MnO2 deliver a high capacity of approximately 1652.2 mA•h•g−1 at a current density of 0.1 A•g−1 after 200 cycles. The high capacity remains at 616.8 mA•h•g−1 (ca. 65.1% capacity retention) at a current density as high as 4 A•g−1. The excellent electrochemical performance indicates that the nMnO2‐srGO hybrid films could be a promising anode material for lithium ion batteries (LIBs).

Flexible Graphene‐Wrapped Carbon Nanotube/Graphene@MnO2 3D Multilevel Porous Film for High‐Performance Lithium‐Ion Batteries

“…As the result of EIS test (Figure S6, Supporting Information), the GCMP anode possesses a lower resistance after long cycling, which is in line with the result of EELS curve. Therefore, the improved interfacial lithium storage and ion‐diffusion kinetics may explain the steady increase of reversible capacity and then the stably high capacity after arriving a balance of the GCMP electrode, which is similar to many metal oxide electrodes …”

“…The change of the curve between 100 °C and around 400 °C is derived from the loss of the residual oxygen‐containing groups in rGO and carbon skeleton. Weight loss between 400 and 800 °C can be ascribed to the transformations from MnO 2 to Mn 2 O 3 phase, and Mn 2 O 3 to Mn 3 O 4 phase . Therefore, the MnO 2 contents are around 91.8% of the CM particles and 64.0% of the GCMP film.…”

Advanced Matrixes for Binder‐Free Nanostructured Electrodes in Lithium‐Ion Batteries

“…[ 26 ] Various metal‐based substrates have been utilized to construct binder‐free nanostructured anodes through the solution deposition method. In the case of Cu substrates, metal‐based oxides, [ 77,82 ] Co/Si nanomountain arrays, [ 79 ] Si/Cu nanocone arrays, [ 81 ] Cu 18 Zn 82 alloys, [ 80 ] and nMnO 2 ‐srGO [ 83 ] have been grown on Cu substrates through ED and used as anodes in LIBs. In particular, 3D spongy structured Cu 18 Zn 82 alloys with different sized macroscopic pores ( Figure a), reported by Varzi et al, [ 80 ] delivered a promising capacity of ≈200 mA h g −1 even at an unconventionally low operational temperature (−20 °C) (Figure 5b).…”

“…The relationship between loading mass of active materials and prices of corresponding supporting matrixes for binder‐free electrodes in LIBs. [ 48–109,141–240 ] ...…”

“…The preparation processes of binder-free nanostructured anodes based on 2D planar metal substrates mainly include the hydro-/ solvothermal method, [48,49,55,57,58] chemical vapor deposition (CVD), [65][66][67] solution deposition, [73][74][75][76][77][78][79][80][81][82][83][84] heat treatment, [73,75,78] magnetron sputtering, [85] and combinations of such techniques. [85][86][87][88][89][90][91] Among them, the simplest preparation method to fabricate a binder-free nanostructured anode is a pencil-drawing preparation approach.…”