Deciphering the lithium storage chemistry in flexible carbon fiber-based self-supportive electrodes

Flexible carbon fiber cloth (CFC) is an important scaffold and/or current collector for active materials in the development of flexible self-supportive electrode materials (SSEMs), especially in lithium-ion batteries. However, during the intercalation of Li ions into the matrix of CFC (below 0.5 V vs. Li/Li+), the incompatibility in the capacity of the CFC, when used directly as an anode material or as a current collector for active materials, leads to difficulty in the estimation of its actual contribution. To address this issue, we prepared Ni5P4 nanosheets on CFC (denoted CFC@Ni5P4) and investigated the contribution of CFC in the CFC@Ni5P4 by comparing to the powder Ni5P4 nanosheets traditionally coated on a copper foil (CuF) (denoted P-Ni5P4). At a current density of 0.4 mA cm(-2), the as-prepared CFC@Ni5P4 showed an areal capacity of 7.38 mAh cm(-2), which is significantly higher than that of the P-Ni5P4 electrode. More importantly, theoretical studies revealed that the CFC has a high Li adsorption energy that contributes to the low Li-ion diffusion energy barrier of the Ni5P4 due to the strong interaction between the CFC and Ni5P4, leading to the superior Li-ion storage performance of the CFC@Ni5P4 over the pristine Ni5P4 sample. This present work unveils the underlying mechanism leading to the achievement of high performance in SSEMs.

Automated summary

This study reveals that Ni5P4 nanosheets prepared on CFC exhibit higher areal capacity and the high Li adsorption energy of CFC contributes to the superior Li-ion storage performance of CFC@Ni5P4.