Highly Pseudocapacitive Storage Design Principles of Heteroatom‐Doped Graphene Anode in Calcium‐Ion Batteries

Abstract

Pseudocapacitive storage of multivalent ions, especially Ca²⁺, in heteroatom‐doped carbon nanomaterials is promising to achieve both high energy and power densities, but there is the lack of pseudocapacitive theories that enable rational design of the materials for calcium‐ion batteries. Herein, the general design principles are established for the anode materials of the batteries via density functional theory calculations and experimental verifications of a series of heteroatom‐doped graphene as an efficient pseudocapacitive anode. A novel descriptor Φ is proposed to correlate the intrinsic properties of dopants with the pseudocapacitive storage properties of the carbon‐based anode. The design principle and descriptor have the predictive ability to screen out the best dual‐doped graphene anode with 10 times higher Ca²⁺ storage capability than that of sole‐doped one, and exceed the current best Ca²⁺ storage anode materials.