Unlocking the dissolution mechanism of phosphorus anode for lithium-ion batteries

Tannic acid-polypyrrole multifunctional coating layer enhancing the interface effect and efficient Li-ion transport of a phosphorus anode

“…(1) The dissolution of lithium polyphosphide (Li x P) intermediates reduces the utilization of phosphorus. 4 (2) The huge volume expansion (over 300%) gives rise to the pulverization of active materials. 5 (3) The sluggish lithiation reaction kinetics severely limit the fast-charging performance.…”

Core–Shell Structure of a Polypyrrole-Coated Phosphorus/Carbon Nanotube Anode for High-Performance Lithium-Ion Batteries

“…Due to the intrinsic intermittency of solar and wind energy, batteries are promising devices for energy storage and transportation. , Lithium-ion batteries (LiBs) have been widely investigated owing to their outstanding specific energy, high stability, and no memory effect. − However, the graphite-based commercial anodes with limited theoretical capacity (372 mAh/g) cannot meet the demand for high energy density. − Black phosphorus (BP), as the most thermodynamically stable allotrope, is considered an ideal candidate for substitution for a graphite-based anode due to its high theoretical capacity (2596 mAh/g), low Li + diffusion energy barrier (0.08 eV), as well as safe and suitable lithiation potential (∼0.7 V vs Li + /Li) for fast charging. − Despite many attractive advantages, the huge volumetric variation (∼300%) during cycling and the unstable electrode/electrolyte interface result in the electrode structure fragmentation and the inferior electrical contact between P and the conductive matrix, further causing rapid capacity degradation and low Coulombic efficiency. ,− Recently, our group reported the dissolution of phosphorus intermediates (Li x Ps) in the electrolyte, leading to a series of critical problems, such as active phosphorus loss and counter electrode corrosion. This is one of the main reasons for capacity decay …”

“…In another case of a vaporization–condensation–conversion method, which can confine phosphorus within specific carbon matrices to enhance the cycle stability, − the phosphorus mass loading is low and difficult to control. Even worse, it is easy to produce white phosphorus in the condensation process, which is toxic and flammable in air, restricting the practical application. , Recently, high-energy ball milling (HEBM) has been considered a convenient approach to prepare nanoscale phosphorus from bulk phosphorus and synthesize BP from red phosphorus (RP). ,− However, the limited electrical contact with carbon materials by mechanical mixing cannot completely solve the series of problems caused by a large volume change, such as the pulverization of phosphorus and the side reaction at the electrode/electrolyte interface. , In addition, the capacity loss caused by the shuttle effect of phosphorus intermediates cannot be suppressed by mixing with carbon materials …”

“…This is one of the main reasons for capacity decay. 22 To date, numerous investigations have demonstrated that reducing the particle size and combining phosphorus with diverse carbonaceous materials are both effective methods to improve the electrochemical properties of phosphorus anodes. Some studies have found that wet-chemical methods can effectively control the particle size and morphology of phosphorus (e.g., hollow phosphorus sphere), which shortens the ion diffusion pathway.…”

“…13,31 In addition, the capacity loss caused by the shuttle effect of phosphorus intermediates cannot be suppressed by mixing with carbon materials. 22 Herein, we prepare a core−shell structure of phosphorus− carbon nanotube@polypyrrole (BP/CNT@PPy) composite via the ball-milling method followed by liquid polymerization for coating. In the core, BP can be synthesized in an effective and economical way starting from red P, and introduction of CNTs can partly buffer the volume expansion of BP.…”