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Anatase TiO 2 Confined in Carbon Nanopores for High‐Energy Li‐Ion Hybrid Supercapacitors Operating at High Rates and Subzero Temperatures
Author(s) -
Fu Wenbin,
Zhao Enbo,
Ma Ruiying,
Sun Zifei,
Yang Yang,
Sevilla Marta,
Fuertes Antonio B.,
Magasinski Alexandre,
Yushin Gleb
Publication year - 2020
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201902993
Subject(s) - materials science , supercapacitor , anatase , electrolyte , chemical engineering , anode , nanopore , graphene , carbon fibers , nanotechnology , capacitance , electrode , composite material , organic chemistry , chemistry , photocatalysis , composite number , engineering , catalysis
Li‐ion hybrid supercapacitors (Li‐HSCs) hold great promise in future electrical energy storage due to their relatively high power and energy density. However, a major challenge lies in the slow kinetics of Li‐ion intercalation/extraction within metal‐oxide electrodes. Here, it is shown that ultrafast charge storage is realized by confining anatase TiO 2 nanoparticles in carbon nanopores to enable a high‐rate anode for Li‐HSCs. The porous carbon with interconnected pore walls and open channels not only works as a conductive host to protect TiO 2 from structural degradation but also provides fast pathways for ion/electron transport. As a result, the assembled cells exhibit remarkable rate capabilities with a specific capacity of ≈140 mAh g −1 at a slow charge and ≈60 mAh g −1 at a 3.5 s fast charge. While the charge/discharge process can be completed as fast as that of state‐of‐the‐art electrical double‐layer capacitors (EDLCs), the produced nanocomposites show three to seven times higher volumetric capacitance than activated carbons used in commercial EDLCs with acetonitrile‐based electrolytes. Equally important for some applications in cold climates or the space, the Li‐HSCs can operate at subzero temperatures as low as −40 °C, which is likely only limited by thermal properties of the acetonitrile (melting point of −45 °C).