High-performance boron-doped silicon micron-rod anode fabricated using a mass-producible lithography method for a lithium ion battery

• Published in: Journal of power sources 2020-04, Vol.454, p.227931, Article 227931
• Main Authors: Cho, Sungjun, Jung, Wonsang, Jung, Gun Young, Eom, KwangSup
• Format: Article
• Language: English
• Subjects: Boron doping level; Boron-doped silicon rod anode; Laser interference lithography; Lithium ion batteries; Metal assisted chemical etching; Surface kinetics
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2020.227931

Although silicon (Si) attracts great attention as a high-capacity anode material in lithium ion batteries (LiBs), a large volume being expanded during charge/discharge (de/lithiation) cycling is a significant problem resulting in a fast capacity fade. To prevent the problem, a variety of Si structures with nano/microscales have been incorporated into the anode, but such structures still have difficulties in terms of mass production. Herein, we present a new way to repetitively produce micron boron (B)-doped Si rods from Si wafer through laser interference lithography (LIL) in combination with the metal assisted chemical etching (MACE) process, enabling the mass-production of multiple Si rods at low cost. Moreover, the effects of the B-doping level of the produced Si rods on the electrochemical LiB performances are studied in detail. As a result, the lightly B-doped Si rod (~1015 atoms cm−3) anodes exhibit the highest initial capacity of 3524 mAh g−1 and cyclic performance, showing a high average Coulombic efficiency (CE) of 98.1% and a capacity fading rate (per cycle) of 0.11% during 500 cycles. It is due to the highest kinetics of de/lithiation on the surface of the lightly B-doped Si rod attributed to favorable phase transition of Si and diffusion of Li ions. •The micron rod shaped Si anodes showed a higher rate capability than Si particles.•Structured Si prevents volume expansion, resulting in an enhanced capacity.•This facile process can enable mass-production through repetitive production.•A lightly B-doped anode exhibits a superior performance for lithium ion battery.•In case of heavily B-doped anode, Li atoms are trapped from the outermost side.