Mn‐Substituted Tunnel‐Type Polyantimonic Acid Confined in a Multidimensional Integrated Architecture Enabling Superfast‐Charging Lithium‐Ion Battery Anodes

Abstract

Abstract Given the inherent features of open tunnel‐like pyrochlore crystal frameworks and pentavalent antimony species, polyantimonic acid (PAA) is an appealing conversion/alloying‐type anode material with fast solid‐phase ionic diffusion and multielectron reactions for lithium‐ion batteries. Yet, enhancing the electronic conductivity and structural stability are two key issues in exploiting high‐rate and long‐life PAA‐based electrodes. Herein, these challenges are addressed by engineering a novel multidimensional integrated architecture, which consists of 0D Mn‐substituted PAA nanocrystals embedded in 1D tubular graphene scrolls that are co‐assembled with 2D N‐doped graphene sheets. The integrated advantages of each subunit synergistically establish a robust and conductive 3D electrode framework with omnidirectional electron/ion transport network. Computational simulations combined with experiments reveal that the partial‐substitution of H3O+ by Mn2+ into the tunnel sites of PAA can regulate its electronic structure to narrow the bandgap with increased intrinsic electronic conductivity and reduce the Li+ diffusion barrier. All above merits enable improved reaction kinetics, adaptive volume expansion, and relieved dissolution of active Mn2+/Sb5+ species in the electrode materials, thus exhibiting ultrahigh rate capacity (238 mAh g−1 at 30.0 A g−1), superfast‐charging capability (fully charged with 56% initial capacity for ≈17 s at 80.0 A g−1) and durable cycling performance (over 1000 cycles).

Keywords

• element substitution
• fast charging anode
• lithium‐ion batteries
• multidimensional architecture
• polyantimonic acid