Reduced Graphene Oxide Films with Ultrahigh Conductivity as Li-Ion Battery Current Collectors

Abstract

Solution processed, highly conductive films are extremely attractive for a range of electronic devices, especially for printed macroelectronics. For example, replacing heavy, metal-based current collectors with thin, light, flexible, and highly conductive films will further improve the energy density of such devices. Films with two-dimensional building blocks, such as graphene or reduced graphene oxide (RGO) nanosheets, are particularly promising due to their low percolation threshold with a high aspect ratio, excellent flexibility, and low cost. However, the electrical conductivity of these films is low, typically less than 1000 S/cm. In this work, we for the first time report a RGO film with an electrical conductivity of up to 3112 S/cm. We achieve high conductivity in RGO films through an electrical current-induced annealing process at high temperature of up to 2750 K in less than 1 min of anneal time. We studied in detail the unique Joule heating process at ultrahigh temperature. Through a combination of experimental and computational studies, we investigated the fundamental mechanism behind the formation of a highly conductive three-dimensional structure composed of well-connected RGO layers. The highly conductive RGO film with high direct current conductivity, low thickness (∼4 μm) and low sheet resistance (0.8 Ω/sq.) was used as a lightweight current collector in Li-ion batteries.

Issues and Challenges Facing Flexible Lithium‐Ion Batteries for Practical Application

“…e) SEM image of the cross‐section for RGO/LFP electrode. f) Cycle performance of the RGO/LFP electrode at a discharge rate of 5 C, where the operating voltage range was 2.0–4.5 V. Reproduced with permission . Copyright 2016, American Chemical Society.…”

Recent Advances in Effective Reduction of Graphene Oxide for Highly Improved Performance Toward Electrochemical Energy Storage

“…[53,54] It has been demonstrated that through significantly lowered structural defects, such highly reduced GO (HRGO) products helped bring about significantly enhanced functional properties for chemical energy storage devices such as metal-ion batteries and supercapacitors (SC), when good crystallinity and associated high electric/ thermal conductivity are essential, as is summarized in Table 1. [55][56][57][58][59] In this work, we focus on reviewing recent advances for the production of HRGO and their applications to chemical energy storage.…”

“…[74] The thermal-reduced graphene-based materials were widely researched and applied to obtain low-defect graphene for energy storage devices. This led to excellent improvement in electrochemical performance of such devices as Li-ion batteries (LIBs), [55,[75][76][77][78][79][80][81][82][83][84] Li-air batteries, [85][86][87][88] Li-sulfur batteries (LSBs), [89] Na-ion batteries (SIBs), [81,90] Al-ion batteries (AlBs), [47][48][49][50] and SCs. [91] Zhang et al [83] used graphite oxide (GO) and triphenylphosphine (TPP) as carbon and phosphorus sources for synthesizing phosphorus-doped graphene (PG) by thermal annealing reduction (e.g., 1000°C).…”

“…Park et al [82] For preparing high-quality graphene, high-temperature annealing was necessary, which helped repair the defects in RGO to obtain well-structured graphene materials. Chen et al [55] firstly reported a high-quality RGO film with an electrical conductivity of up to 3112 S cm…”

The influence of substrate material on the resistance of composite films based on reduced graphene oxide and polystyrene

“…There are many studies devoted to the conductivity of graphene oxide in polymer composites [1][2][3][4][5][6][7][8]. Graphene oxide is a dielectric, but with appropriate treatment its band gap can be decreased to zero [9,10].…”