Tungsten nitride nanoparticles anchored on porous borocarbonitride as high-rate anode for lithium ion batteries

Abstract

Electrode materials play a paramount role in developing high-performance lithium ion batteries (LIBs). Nanostructured electrode materials can offer unique advantages, such as high rate capability. Here, we describe a strategy for synthesizing advanced anode materials with tungsten nitride (WN) quantum dots (2–5 nm) firmly anchored on mesoporous ternary borocarbonitride (BCN). A composite sample exhibited reversible capacities of 683.4 and 366.9 mAh g−1 at current densities of 0.1 and 4 A g−1, respectively, suggesting good rate capability. The electrode is also stable against cycling with only 2.7% capacity loss after 500 cycles at 1 A g−1. This high performance can be ascribed to the highly dispersed WN quantum dots, which provide a high active surface for lithium ions, and significantly shortened pathways for charge transport. In addition, the porous BCN framework facilitates transfer of the electrolyte and offers a strong binding interaction with the WN quantum dots to alleviate the volume expansion and particle agglomeration issues. Further analysis of lithium storage kinetics revealed the important role that the pseudocapacitive mechanism played in the charge storage process. This work demonstrates the great potential of tungsten-based composite as high-rate anode for high-performance LIBs.