Sunday, 29 May 2022: 09:40
West Meeting Room 120 (Vancouver Convention Center)
The porous carbon materials with well-controlled pore size distribution and large specific surface area (SSA) are attracting attention in energy storage applications. Here, we introduce a new strategy for micropore formation by resorcinol-formaldehyde (RF) resin conformation change through the addition of melamine. The addition of melamine generated a change of RF resin unit chemical structure from benzenoid-benzenoid (B:B) unit to quinoid-benzenoid (Q:B) unit. This change of RF unit structure transformed linear resin conformation to coiled resin conformation with more micropore formation in RF resin. Hollow carbon (HC) structure was synthesized through the RF resin carbonization process and silica template. The SSA of Q:B HC (2912.1 m2 g−1) derived from coiled conformation was determined to be about 12-fold higher than B:B HC (245.2 m2 g−1) derived from linear conformation. As-synthesized Q:B hollow carbon (Q:B HC) structure provide not only fast ion diffusion channel through the hollow core but also rich micropores being active sites for high capacity as a capacitor-type cathode. These Q:B HC exhibited 5-fold higher energy storage capacity (111.3 mAh g−1) than those of B:B HC (20.8 mAh g−1).
Meanwhile, Ge precursor is added during RF resin polymerization process to form molecular-cluster GeOx embedded Q:B HC (Ge-Q:B HC) for the battery-type anode. The Ge precursor was trapped in the void space which generated by the RF resin conformation change, so molecular size GeOx cluster could be embedded in polymer network, and the local coordination environment of Ge could be confirmed through XAFS analysis. Molecular-cluster size of GeOx can suppress volume expansion stress for longer cycle stability and facilitate Li-ion diffusion faster to high kinetic performance compared to bulk size Ge. Additionally, this Q:B HC and Ge-Q:B HC are assembled into lithium ion capacitor hybrid energy storage configurations to achieve high energy density up to 253Wh kg-1 in 226W kg-1 and 90.1% high capacity retention with 7000 cycles performance.
Meanwhile, Ge precursor is added during RF resin polymerization process to form molecular-cluster GeOx embedded Q:B HC (Ge-Q:B HC) for the battery-type anode. The Ge precursor was trapped in the void space which generated by the RF resin conformation change, so molecular size GeOx cluster could be embedded in polymer network, and the local coordination environment of Ge could be confirmed through XAFS analysis. Molecular-cluster size of GeOx can suppress volume expansion stress for longer cycle stability and facilitate Li-ion diffusion faster to high kinetic performance compared to bulk size Ge. Additionally, this Q:B HC and Ge-Q:B HC are assembled into lithium ion capacitor hybrid energy storage configurations to achieve high energy density up to 253Wh kg-1 in 226W kg-1 and 90.1% high capacity retention with 7000 cycles performance.