Constructing a Micrometer-Sized Structure through an Initial Electrochemical Process for Ultrahigh-Performance Li + Storage.

Orthorhombic niobium pentoxide (T-Nb 2 O 5 ) is a promising anode to fulfill the requirements for high-rate Li-ion batteries (LIBs). However, its low electric conductivity and indistinct electrochemical mechanism hinder further applications. Herein, we develop a novel method to obtain a micrometer-sized layer structure of S-doped Nb 2 O 5 on an S-doped graphene (SG) surface (the composite is denoted S-Nb 2 O 5 /SG) after the initial cycle, which we call " in situ electrochemically induced aggregation". In situ and ex situ characterizations and theoretical calculations were carried out to reveal the aggregation process and Li + storage process. The unique merits of the composite with a micrometer-sized layer structure increased the reaction degree, structural stability, and electrochemical kinetics. As a result, the electrode exhibited a large capacity (∼598 mAh g -1 at 0.1 A g -1 ), outstanding cycling stability (∼313 mAh g -1 at 5 A g -1 and remains at ∼313 mAh g -1 after 1000 cycles), and a high Coulombic efficiency and has a high fast-charging performance and excellent cycling stability.