In‐Situ Templating Growth of Homeostatic GeP Nano‐Bar Corals with Fast Electron‐Ion Transportation Pathways for High Performance Li‐ion Batteries

Abstract

As a nascent anode material for lithium-ion batteries (LIBs) , layered germanium phosphide (GeP) boasts excellent potential due to its high capacity , decent conductivity, and excellent theoretically calculated Li + diffusion coefficient. However, in reality, GeP usually suffers from relatively slow Li + diffusion and poor cycling stability associated with its stiff bulky structure as synthesized using conventional mixing-sintering method, in which the predicted quickest electron-ion transport pathways tend to be concealed. Herein, for the first time, we propose an in-situ template method to directionally induce the construction of GeP nanobar (GeP-nb) coral s with an adjustable aspect ratio . The GeP nanobars grown onto conductive matrix with high aspect ratio expose more quickest electron-ion transportation facets for fast reaction dynamics, which not only is the first verification of the theoretical prediction, but also reveals the underlying mechanism of crystal orientation optimization on the electrochemical behavior of GeP-based materials. Besides, the customized GeP-nb electrode delivers a self-healable homeostatic behavior by reversibly stabilizing GeP crystalline structure through multi-phase reactions to maintain structural integrity and cycling stability (850 mAh g -1 at 1 A g -1 after 500 cycles). As a result, the GeP-nb presents the highest Li + diffusion coefficient (6.21×10 -11 cm 2 s -1 ) among all the Ge-based anode materials studied so far, rendering an excellent rate performance (620 mAh g -1 at 5 A g -1 ) as a LIBs anode. This unique in-situ structural regulation strategy for improved ion diffusion points to a valuable roadmap for the rational design of novel electrode materials for futuristic high energy density batteries.