Built-In Electric Field Generated by the Piezoelectric Effect Facilitates a High Li+ Diffusion Rate for Li-Ion Batteries

Silicon (Si), which is a promising anode for lithium-ion batteries (LIBs), has attracted widespread concern on account of its high theoretical capacity. Unfortunately, the Si volume expansion during cycling leads to serious capacity fading, which greatly impedes the application prospect of Si electrodes. In this work, BaTiO3 (BTO) was introduced to prepare one Si/BaTiO3@Carbon nanofiber material (Si/BTO@CNF). The volume expansion of Si inevitably induces the piezoelectric potential of BTO during cycling. Such a beneficial built-in electric field greatly facilitates the diffusion rate of LIBs. The assembled Si/BTO@CNF|Li asymmetric battery maintained a reversible capacity of 1428 mAh·g–1 after 200 cycles at 500 mA·g–1. Meanwhile, the Li+ diffusion rate and reaction kinetics were significantly improved. This in situ construction of a built-in electric field strategy based on BTO is expected to accelerate the practical application of high-performance Si-based LIBs.