Sustainable Encapsulation Strategy of Silicon Nanoparticles in Microcarbon Sphere for High-Performance Lithium-Ion Battery Anode
Hyeon‐Ji Shin, Jang‐Yeon Hwang, Hyun J. Kwon, Won‐Jin Kwak, Sang‐Ok Kim, Hyung‐Seok Kim, Hun‐Gi Jung
Abstract
Owing to the high theoretical capacity, low operating potentials, and natural abundance, silicon (Si) is considered as one of the most promising anode materials for lithium-ion batteries. However, a large volume change during alloying–dealloying often results in pulverization, electrical contact loss, and unstable solid-electrolyte interphase (SEI) formation, leading to rapid capacity fading. We present a rational encapsulation strategy of a silicon–carbon (Si–C) composite as a high-performance anode material for lithium-ion batteries (LIBs). The Si–C composite material is prepared via a one-pot hydrothermal method by using silicon nanoparticles modified using an etching route and sucrose as a carbon precursor. The proposed Si–C composite material has a meso-macroporous structure and contains a large weight fraction of silicon nanoparticles (40 wt %) encapsulated in a micrometric carbon sphere (∼3 μm). In the composite material, the carbon framework tightly encapsulates the silicon nanoparticles to the interior of the particle, which not only provides electrical conductivity but also decreases the stress/strain of the material during the alloying–dealloying process. The material demonstrates high initial capacity of 1300 mAh g–1, excellent capacity retention of 90% after 200 cycles, and fast charging–discharging capability within 12 min. We believe that the proposed encapsulation strategy here will be helpful in developing a high-energy and low-cost Si–C composite anode.