Black Phosphorus Degradation during Intercalation and Alloying in Batteries

Abstract

Numerous layered materials are being recognized as promising candidates for high-performance alkali-ion battery anodes, but black phosphorus (BP) has received particular attention. This is due to its high specific capacity, due to a mixed alkali-ion storage mechanism (intercalation-alloying), and fast alkali-ion transport within its layers. Unfortunately, BP based batteries are also commonly associated with serious irreversible losses and poor cycling stability. This is known to be linked to alloying, but there is little experimental evidence of the morphological, mechanical, or chemical changes that BP undergoes in operational cells and thus little understanding of the factors that must be mitigated to optimize performance. Here the degradation mechanisms of BP alkali-ion battery anodes are revealed through operando electrochemical atomic force microscopy (EC-AFM) and ex situ spectroscopy. Among other phenomena, BP is observed to wrinkle and deform during intercalation but suffers from complete structural breakdown upon alloying. The solid electrolyte interphase (SEI) is also found to be unstable, nucleating at defects before spreading across the basal planes but then disintegrating upon desodiation, even above alloying potentials. By directly linking these localized phenomena with the whole-cell performance, we can now engineer stabilizing protocols for next-generation high-capacity alkali-ion batteries.

Investigating the mechanism of phosphorene nanoribbon synthesis by discharging black phosphorus intercalation compounds

“…24,33 Given the expansion/layer shearing of the BP framework upon charging, it is assumed that some of the strain effects on the BP crystal from intercalation of Li remain after the crystal is discharged with PhCN, which would be concurrent with some P–P bond weakening, consistent with work by Karki et al , 32 and shown recently from ex situ Raman spectroscopy of BP electrodes electrochemically intercalated and de-intercalated with Na. 34…”

High-performance Si@C anode for lithium-ion batteries enabled by a novel structuring strategy

“…67 Moreover, the Raman peak of the pure Si electrode has a more significant downshift and a more increased full width at half-maximum than that of Si@FeNO@P after the cycles, indicating worse structural stability. 68 The chemical states of the Si and Si@FeNO@P electrodes before and after 50 cycles were further investigated, as revealed in Fig. 7d.…”

“…67 Moreover, the Raman peak of the pure Si electrode has a more significant downshift and a more increased full width at half-maximum than that of Si@FeNO@P after the cycles, indicating worse structural stability. 68…”

Inducing Rigidity in Layered Structures for Improved Anodic Performance in Magnesium-Ion Battery: A Computational Design

“…However, as the state-of-charge (SOC) progresses (Mg loading), BP experiences substantial volumetric expansion, leading to the disruption of P–P bonds within layers . Both theoretical and experimental studies have indicated that the origin of such structural breakdown of BP anode is the Mg–P alloying at high SOC. This phenomenon results in poor rate performance and reduced cycling efficiency for the BP anode …”

“…Notably, orthorhombic black phosphorus (BP), which is the thermodynamically most stable allotrope of phosphorus under ambient conditions, stands out due to its puckered layered structure. , BP exhibits similar intercalation chemistry to graphite, but with a corrugated interlayer spacing that can accommodate Mg-ions, offering significant storage capacity at sufficiently low potential . However, as the state-of-charge (SOC) progresses (Mg loading), BP experiences substantial volumetric expansion, leading to the disruption of P–P bonds within layers . Both theoretical and experimental studies have indicated that the origin of such structural breakdown of BP anode is the Mg–P alloying at high SOC.…”