Amorphous Red Phosphorus Embedded in Highly Ordered Mesoporous Carbon with Superior Lithium and Sodium Storage Capacity

Abstract

Red phosphorus (P) have been considered as one of the most promising anode material for both lithium-ion batteries (LIBs) and (NIBs), because of its high theoretical capacity. However, natural insulating property and the large volume expansion of red P during cycling lead to poor cyclability and low rate performance, which prevents its practical application. Here, we significantly improves both lithium storage and sodium storage performance of red P by confining nanosized amorphous red P into the mesoporous carbon matrix (P@CMK-3) using a vaporization-condensation-conversion process. The P@CMK-3 shows a high reversible specific capacity of ∼ 2250 mA h g(-1) based on the mass of red P at 0.25 C (∼ 971 mA h g(-1) based on the composite), excellent rate performance of 1598 and 624 mA h g(-1) based on the mass of red P at 6.1 and 12 C, respectively (562 and 228 mA h g(-1) based on the mass of the composite at 6.1 and 12 C, respectively) and significantly enhanced cycle life of 1150 mA h g(-1) based on the mass of red P at 5 C (500 mA h g(-1) based on the mass of the composite) after 1000 cycles for LIBs. For Na ions, it also displays a reversible capacity of 1020 mA h g(-1) based on the mass of red P (370 mA h g(-1) based on the mass of the composite) after 210 cycles at 5C. The significantly improved electrochemical performance could be attributed to the unique structure that combines a variety of advantages: easy access of electrolyte to the open channel structure, short transport path of ions through carbon toward the red P, and high ionic and electronic conductivity.

Nano-structured red phosphorus/porous carbon as a superior anode for lithium and sodium-ion batteries

“…Preparation of P@AC@CNT composites: P@AC@CNT composite was synthesized via a sublimation-condensation-conversion method [9]. 0.9 g of the commercial red P (Sinopharm Chemical Reagent Co., Ltd, China) was mixed with 0.3 g AC@CNT and the mixture was placed in a sealed stainless steel vessel under Ar atmosphere.…”

“…The electrochemical performances of P@AC@CNTs were characterized using cyclic voltammetry (CV) and the galvanostatic charge/discharge (GCD) method over the potential range of 0.001-2.5 V and 0.001-2.0 V for LIBS and NIBS, respectively. For the rate performance, the C-rate of the composite was calculated by the following equation [9]:…”

“…Recently, Na-ion batteries (NIBs) have attracted widespread attention as a potential alternative to LIBs due to their earth abundance, low cost and low redox potential [6,7]. There is an increasing demand for LIBs with higher energy density, which facilitates the study of various LIB electrode materials [8][9][10]. The same impetus also drives current NIB research [11][12][13].…”

“…However, the practical application of red P in batteries is severely hindered by its low electronic conductivity (~10-14 S cm −1 ) and significant volume change during charging/ discharging process (~300% and~400% in LIB and NIB applications, respectively) [26,[29][30][31][32]. These limitations cause the fracture of the electrode material during cycling, rapid capacity decay, and poor electrochemical performance at high charging/discharging rate [9].…”

“…Such P/C composites show both high specific capacity and initial Coulombic efficiency (ICE); however, the rate performance and cycle life are insufficient for practical applications. Through the sublimation-condensationconversion method, red P is confined to the surface or the pores of the carbon structures (e.g., single CNTs [26], graphene [32], activated carbon (AC) [31], ordered mesoporous carbon [9], micro-porous carbon [27], and others [34]). The resulting composites show both good rate performance and long cycle life in batteries.…”