Red phosphorus coated by buckwheat-derived hard carbon as an anode material for lithium-ion batteries

Red phosphorus (RP) is seen as a promising candidate for the anode component in lithium-ion batteries (LIBs) due to its impressive theoretical specific capacity of 2596 mAhg- 1. Nevertheless, its commercial viability is hindered by issues related to poor conductivity and significant volume fluctuations during cycling. Among the ways to improve the electrochemical characteristics of RP as an anode are nanostructuring, advanced electrolytes, optimized electrode design, and carbon coating. Herein, we show the facile way to prepare the improved RP-based anode, just adding 30 % hard carbon (HC) obtained from toasted buckwheat seeds. During electrochemical tests, it was revealed the RP@HC composite showed higher discharge and charge capacities of 1949.80 mAhg- 1 and 1286.90 mAhg- 1 as well as better cycling performance than its pure counterpart, which experienced immediate fade after the 1st cycle. The dQ/dV and post-mortem analyses confirmed that the developed electrode still maintains the electrochemical reaction and the mechanical connection with the current collector after 100 cycles. The improvement has been attributed to the beneficial structure of the RP@HC anode, which acquired high conductivity and better mechanical stability. This work demonstrated that using the HC prepared from the buckwheat seeds, it is possible to enhance the electrochemical performance of RP material.