Electrolyte additive engineering is one of the most useful approaches to improve the interfacial property of electrode material in Li-ion batteries (LIBs), which plays a vital role in the mass transport during the electrochemical process. Boron-based electrolyte additives have a good application prospect, however exploring new additives with lower-cost and higher efficiency is still needed. In this study, Phenyl boric acid (PBA), acting as a two-sided interface modifier, is introduced to LiNi0.5Co0.2Mn0.3O2/SiC batteries. Through both theoretical calculations and experimental measurements, it is found that PBA could be preferentially reduced on the SiC anode and induce the formation of B-rich solid electrolyte interphase (SEI), which efficiently protects the anode material from the parasitic reaction. Besides, PBA can be sacrificially oxidized before other salt/solvent decomposition, achieving a highly-reversible lithiation/delithiation process at the cathode. Benefiting from these synergistic effects, the target Si-C/Li half-cells achieve a 2.5 % improvement in average coulomb efficiency of 100 cycles, while the capacity retention rate of NCM/Li half-cells and NCM/Si-C full cells increase by 21.4 % and 15.8 %, respectively. This work provides an effective approach to ameliorating the electrode interface chemistry of LIBs employing Si-based anodes Ni-rich cathodes and another analogous battery systems.