Pushing the Limits: 3D Layer-by-Layer-Assembled Composites for Cathodes with 160 C Discharge Rates

Abstract

Deficiencies of cathode materials severely limit cycling performance and discharge rates of Li batteries. The key problem is that cathode materials must combine multiple properties: high lithium ion intercalation capacity, electrical/ionic conductivity, porosity, and mechanical toughness. Some materials revealed promising characteristics in a subset of these properties, but attaining the entire set of often contrarian characteristics requires new methods of materials engineering. In this paper, we report high surface area 3D composite from reduced graphene oxide loaded with LiFePO4 (LFP) nanoparticles made by layer-by-layer assembly (LBL). High electrical conductivity of the LBL composite is combined with high ionic conductivity, toughness, and low impedance. As a result of such materials properties, reversible lithium storage capacity and Coulombic efficiency were as high as 148 mA h g(-1) and 99%, respectively, after 100 cycles at 1 C. Moreover, these composites enabled unusually high reversible charge-discharge rates up to 160 C with a storage capacity of 56 mA h g(-1), exceeding those of known LFP-based cathodes, some of them by several times while retaining high content of active cathode material. The study demonstrates that LBL-assembled composites enable resolution of difficult materials engineering tasks.

Recent Developments on and Prospects for Electrode Materials with Hierarchical Structures for Lithium‐Ion Batteries

“…[80] The composite had a particle size of 20−40 nm with a carbon layer thickness of 1−2 nm, which delivered a capacity of 90 mAh g −1 at 10 A g −1 (58.8 C) and had less than 5% capacity loss after 1100 cycles at 0.1 A g −1 . [84] The LiFePO 4 /rGO composite displayed discharge capacities of 146, 121, 81, and 56 mAh g −1 at 1, 10, 80, and 160 C, respectively. Guo and co-workers reported double nanocarbon (amorphous carbon and graphitized carbon nanotubes (CNTs)) modified LiFePO 4 nanoparticles, which were synthesized via a polyol route combined with a carbon-coating procedure.…”

“…[ LiFePO 4 has a theoretical specific capacity of 170 mAh g −1 based on the Fe 3+ /Fe 2+ couple and features only slight volume change (6.81%) during the charge-discharge process, but it suffers from low intrinsic electronic conductivity (≈10 −9 S cm −1 ). [79][80][81][82][83][84][85] Zhou and co-workers designed and prepared a core-shell-structured LiFePO 4 /C nanocomposite via an in situ polymerization restriction method using FePO 4 /polyaniline precursor. [79][80][81][82][83][84][85] Zhou and co-workers designed and prepared a core-shell-structured LiFePO 4 /C nanocomposite via an in situ polymerization restriction method using FePO 4 /polyaniline precursor.…”

Water‐Based Assembly of Polymer–Metal Organic Framework (MOF) Functional Coatings

“…A wide variety of substrates are amenable to LbL assembly, ranging from silicon and glass to even textiles and Teflon . Materials including polyelectrolytes, nanoparticles, zeolites, metal oxides, and DNA have been successfully assembled for applications such as energy storage, membrane separations, and drug delivery . Despite the versatility of LbL assembly, it is not immediately obvious as to whether MOF particles can be assembled because of existing challenges with tailoring their dispersibility in water and surface charge.…”

3D nitrogen-doped graphene foam with encapsulated germanium/nitrogen-doped graphene yolk-shell nanoarchitecture for high-performance flexible Li-ion battery

“…To tackle above challenges, numerous research efforts have been directed to three-dimensional (3D) interconnected graphene network (such as aerogels, hydrogels and foams) as current collector or matrix via hydrothermal, layer-by-layer assembly and chemical vapour deposition methods in recent years1314151617. Chemical vapor deposition (CVD) is a promising method to synthesize graphene with higher conductivity than other chemical synthesis, which would facilitate the fast electron and ion transport in advanced energy storage system.…”