Direct Access to Hierarchically Porous Inorganic Oxide Materials with Three-Dimensionally Interconnected Networks

Hierarchically porous oxide materials have immense potential for applications in catalysis, separation, and energy devices, but the synthesis of these materials is hampered by the need to use multiple templates and the associated complicated steps and uncontrollable mixing behavior. Here we report a simple one-pot strategy for the synthesis of inorganic oxide materials with multiscale porosity. The inorganic precursor and block copolymer are coassembled into an ordered mesostructure (microphase separation), while the in situ-polymerized organic precursor forms organic-rich macrodomains (macrophase separation) around which the mesostructure grows. Calcination generates hierarchical meso/macroporous SiO₂ and TiO₂ with three-dimensionally interconnected pore networks. The continuous 3D macrostructures were clearly visualized by nanoscale X-ray computed tomography. The resulting TiO₂ was used as the anode in a lithium ion battery and showed excellent rate capability compared with mesoporous TiO₂. This work is of particular importance because it (i) expands the base of BCP self-assembly from mesostructures to complex porous structures, (ii) shows that the interplay of micro- and macrophase separation can be fully exploited for the design of hierarchically porous inorganic materials, and therefore (iii) provides strategies for researchers in materials science and polymer science

Mesoporous Ge/GeO₂/Carbon Lithium-Ion Battery Anodes with High Capacity and High Reversibility

We report mesoporous composite materials (m-GeO₂, m-GeO₂/C, and m-Ge-GeO₂/C) with large pore size which are synthesized by a simple block copolymer directed self-assembly. m-Ge/GeO₂/C shows greatly enhanced Coulombic efficiency, high reversible capacity (1631 mA h g^–1), and stable cycle life compared with the other mesoporous and bulk GeO₂ electrodes. m-Ge/GeO₂/C exhibits one of the highest areal capacities (1.65 mA h cm^–2) among previously reported Ge- and GeO₂-based anodes. The superior electrochemical performance in m-Ge/GeO₂/C arises from the highly improved kinetics of conversion reaction due to the synergistic effects of the mesoporous structures and the conductive carbon and metallic Ge

Advanced Hybrid Supercapacitor Based on a Mesoporous Niobium Pentoxide/Carbon as High-Performance Anode

Recently, hybrid supercapacitors (HSCs), which combine the use of battery and supercapacitor, have been extensively studied in order to satisfy increasing demands for large energy density and high power capability in energy-storage devices. For this purpose, the requirement for anode materials that provide enhanced charge storage sites (high capacity) and accommodate fast charge transport (high rate capability) has increased. Herein, therefore, a preparation of nanocomposite as anode material is presented and an advanced HSC using it is thoroughly analyzed. The HSC comprises a mesoporous Nb₂O₅/carbon (m-Nb₂O₅–C) nanocomposite anode synthesized by a simple one-pot method using a block copolymer assisted self-assembly and commercial activated carbon (MSP-20) cathode under organic electrolyte. The m-Nb₂O₅–C anode provides high specific capacity with outstanding rate performance and cyclability, mainly stemming from its enhanced pseudocapacitive behavior through introduction of a carbon-coated mesostructure within a voltage range from 3.0 to 1.1 V (<i>vs</i> Li/Li⁺). The HSC using the m-Nb₂O₅–C anode and MSP-20 cathode exhibits excellent energy and power densities (74 W h kg^–1 and 18 510 W kg^–1), with advanced cycle life (capacity retention: ∼90% at 1000 mA g^–1 after 1000 cycles) within potential range from 1.0 to 3.5 V. In particular, we note that the highest power density (18 510 W kg^–1) of HSC is achieved at 15 W h kg^–1, which is the highest level among similar HSC systems previously reported. With further study, the HSCs developed in this work could be a next-generation energy-storage device, bridging the performance gap between conventional batteries and supercapacitors