Internal and External Cultivation Design of Zero‐Strain Columbite‐Structured MNb 2 O 6 toward Lithium‐Ion Capacitors as Competitive Anodes

Modest rate behaviors and structural collapse of battery‐type anodes limit the commercial application of lithium‐ion capacitors (LICs). For this, rational design of advanced anodes with both structural stability and high ionic/electronic conductivities becomes essential to advanced LICs. Herein, a general avenue is developed to construct a series of single‐crystal nano‐blocks assembled as “zero‐strain” columbite‐structured MNb 2 O 6 (M = Cd, Co, Zn, Mn, Mg, Ca) accordion frameworks toward LICs. The intrinsic Li + (de)insertion involves a solid‐solution charge storage mechanism with a volumetric change of