Observation of High-Capacity Monoclinic B-Nb 2 O 5 with Ultrafast Lithium Storage

Apart from Li Ti O , there are few anode substitutes that can be used in commercial high-power lithium-ion batteries. Orthorhombic T-Nb O has recently been proven to be another substitute anode. However, monoclinic B-Nb O of same chemistry is essentially inert for lithium storage, but the underlying reasons are unclear. In order to activate the "inert" B-Nb O , herein, nanoporous pseudocrystals to achieve a larger specific capacity of 243 mAh g than Li Ti O (theoretical capacity: 175 mAh g ) are proposed. These pseudocrystals are rationally synthesized via a "shape-keep" topological microcorrosion process from LiNbO precursor. Compared to pristine B-Nb O , experimental investigations reveal that B-Nb O delivers ≈3000 times higher electronic conductivity and tenfold enhanced Li diffusion coefficient. An ≈30% reduction of energy barrier for Li-ion migration is also confirmed by the theoretical calculations. The nanoporous B-Nb O delivers unique ion/electron transport channels to proliferate the reversible and deeper lithiation, which activate the "inert" B-Nb O . The capacitive-like behavior is observed to endow B-Nb O ultrafast lithium storage ability, harvesting 136 mAh g at 100 C and 72 mAh g even at 250 C, superior to Li Ti O . Pouch-type full cells exhibit the energy density of ≈251 Wh kg and ultrahigh power density up to ≈35 kW kg .