P-type Cathode Material Design Guided by Material Descriptors for High-energy Density Sodium Batteries

Abstract

P-type organic electrode materials (OEMs) face considerable challenges in constructing high-energy density sodium metal batteries (SMBs) due to the low capacity. To preserve their voltage advantage, developing effective structural design strategies is essential. However, the lack of material descriptors hampers the efficiency of material design and screening. Herein, two material descriptors: the benzene ring/active nitrogen (R/N) ratio and energy density factor (Ef) are established to guide high-energy density SMB design. As proof of concept, triphenylamine (TPA, 3 R/N ratio and 573.6 Ef value) and a porous organic polymer condensation of triiodotriphenylamine and dihydrophenazine named p-PZA POP (1.5 R/N ratio and 907.5 Ef value) are chosen. As a result, the p-PZA POP achieves a high energy density of 524.6 Wh kg-1 at 1 A g-1, nearly double that of TPA (273.3 Wh kg-1). Remarkably, p-PZA POP demonstrates excellent wide-temperature electrochemical performance from 50 °C (166.2 mAh g-1 at 1 A g-1) to -20 °C (141.6 mAh g-1 at 0.1 A g-1). This work establishes a theoretical framework for the rational design and screening of high-performance p-type OEMs through predictive material descriptors.