Phosphorus‐Modulation‐Triggered Surface Disorder in Titanium Dioxide Nanocrystals Enables Exceptional Sodium‐Storage Performance

Take the strain: A phosphorus modulation of anatase TiO₂ simultaneously triggers a surface phase transition, which gives structural disorder, and interior atomic‐level P‐doping. These two beneficial changes result in a zero‐strain during sodium‐ion insertion/extraction which occurs with only about 0.1 % volume variation and thus enables an exceptional sodium‐storage performance.

Abstract

Structural modulation and surface engineering have remarkable advantages for fast and efficient charge storage. Herein, we present a phosphorus modulation strategy which simultaneously realizes surface structural disorder with interior atomic‐level P‐doping to boost the Na⁺ storage kinetics of TiO₂. It is found that the P‐modulated TiO₂ nanocrystals exhibit a favourable electronic structure, and enhanced structural stability, Na⁺ transfer kinetics, as well as surface electrochemical reactivity, resulting in a genuine zero‐strain characteristic with only approximately 0.1 % volume variation during Na⁺ insertion/extraction, and exceptional Na⁺ storage performance including an ultrahigh rate capability of 210 mAh g⁻¹ at 50 C and a strong long‐term cycling stability without significant capacity decay up to 5000 cycles at 30 C.

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