Sluggish reaction kinetics induced by the inferior solid-state ion diffusion and poor conductivity of electrode materials currently conflict with increasing fast-charge needs for sodium ion batteries (SIBs) based on conversion… Click to show full abstract
Sluggish reaction kinetics induced by the inferior solid-state ion diffusion and poor conductivity of electrode materials currently conflict with increasing fast-charge needs for sodium ion batteries (SIBs) based on conversion mechanism. Herein, mesoporous, conductive, thin-wall three-dimension (3D) skeletons of molybdenum nitride (meso-Mo2N) were established and employed as anodes to facilitate rate performance for SIBs. Mesoporous channels (~9.3 nm) with very thin walls (<8 nm) and conductive networks in meso-Mo2N enable the rapid Na+/Li+ infiltrability/diffusivity and smooth electron transfer, respectively. The fast ion diffusion/transfer ability is confirmed by galvanostatic intermittent titration technique, cyclic voltammetry tests with higher ion-diffusion dominated capacity and larger Na+ diffusion coefficient. Consequently, meso-Mo2N exhibited a superior rate capability and a stable specific capacity of 158 mAh g-1 (after 1000 cycles) at 1 A g-1 for SIBs, surpassing nonporous Mo2N and even the previously reported Mo2N. Furthermore, the proof of concept can be also extended to enhanced Li storage. Such mesostructured design with 3D mesoporous, conductive thin wall of electrodes is a promising strategy for achieving fast-charging and high-performance Na/Li storage.
               
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