Engineering Heterostructure-Incorporated Metal Silicates Anchored on Carbon Nanotubes for Highly Durable Lithium Storage
Qiushi Wang, Yuhang Li, Tao Meng, Binbin Huang, Lei Hu, Hongjie Su, Changgong Meng, Yexiang Tong
Abstract
Although transition metal silicates are recognized as high potential and attractive materials for next-generation lithium-ion batteries (LIBs) due to their efficient energy storage, earth-abundance without pollution, low cost, and easy preparation, however, the unstable electrochemical stability originating from the intrinsic mechanism involved in long-term cycling tests is always of concern and needs to be decoupled stepwise. Herein, a strategy is proposed to overcome the challenges through the construction of a heterostructure using a facile hydrothermal method in combination with carbon nanotubes (CNTs), the composite. By tailoring a capacitive contribution over diffusion toward total charge storage in the heterostructure, CNT-coated heterostructural copper–nickel silicates (CNT@NiCuSi) were employed as the anode to achieve a relatively high capacity (412 mAh g–1 at 0.2 A g–1) and prolonged life for durable LIBs (91% retention after 1000 cycles at 0.5 A g–1). The heterostructure generated by NiSi/CuSi could lower the polarization of the composite and elevate its cycle stability, rendering the metal silicate favorable for LIBs. As a consequence, the practical application is evaluated by assembling a full cell based on CNT@NiCuSi as the anode and LiNi0.8Co0.1Mn0.1O2 (NCM811) as the cathode yielding a reversible capacity of 429 mAh g–1, along with a decent capacity retention of 221 mAh g–1 at a current density of 0.5 A g–1 after 300 cycles. This strategy opens an avenue for constructing long-life metal silicate-based nanocomposites for LIBs.