Two-dimensional layered chromium selenophosphate: advanced high-performance anode material for lithium-ion batteries

The demands of the energy storage market for better performing lithium-ion batteries (LIBs) are enormous and ever-increasing. Following this trend, new electrode materials with higher energy and power densities should be developed to reach the electrode requirements of next-generation batteries. With this in mind, we present a novel composite (CrPSe3-G-MWCNT@NiB) that combines diverse characteristics of the excellent Li storage properties of 2D layered chromium selenophosphate (CrPSe3), the high conductivity and specific surface area of carbon-based materials [graphite (G) and multi-walled carbon nanotubes (MWCNTs)], and the abundant coordinative unsaturated sites of Ni-B nanoflakes. The composites were synthesized via a process involving three stages: (a) a one-step high-temperature solid-phase 2D CrPSe3 preparation, (b) high-energy ball milling integration with the carbon materials, and (c) a fast interface chemical reduction coating with the Ni-B nanoflakes. It is demonstrated that the optimized CrPSe3-G-MWCNT@NiB composites exhibit a remarkable electrochemical response in lithium half-cells, delivering around 657 mAh g(-1) after 200 cycles, as well as a significantly longer cycle life, higher rate capability and lower charge/discharge polarization in comparison with the bulk CrPSe3. Galvanostatic studies also revealed that the CrPSe3-G-MWCNTs@NiB electrode displays a remarkable electrochemical property, which enable its application in lithium full cells, with a capacity of 123 mAh g(cathode) (-1) after 40 cycles and a high Coulombic efficiency (over 99.1%). Thus, the integration of the carbon materials and Ni-B nanoflakes into the presented composite makes it a particularly promising candidate anode for use in high performance LIBs.