## 3 Results
### The Forward-Citation Information  
Citation counts were analyzed using the Derwent Innovation System. As aforementioned, high forward citation counts indicate that the patents of interest might have greater technological innovation or impact than others. Forward citation analysis is thus believed to be helpful in shedding light in the technological development. In this study, electrolyte compositions disclosed in these patents could be explored, as they were more frequently referred by the successive inventions that were considered more by competitors in the LIBs industry. Figure 3 illustrates that the top 10 patents were owed by Mitsubishi Chem. (4), Panasonic (3), Samsung SDI (2), and LG Chem. (1). Among these patents, seven patents were from the Japanese companies, Mitsubishi Chem. and Panasonic. It further means that Mitsubishi Chem.'s invention had a more prominent impact on the following inventions. The top 10 patents with high forward-citation counts were considered, and patent information were extracted and summarized in support information. Patent numbers, assignee name, forward citation counts, and electrolyte composition were described there.  
There were two patents with the highest patent citation counts. One was US7083878B2 (published on 1 August 2006) by Mitsubishi Chem. An objective of the invention is to reduce the gas generation, while providing the battery with high capacity, excellent storage, charging/discharging, and cycling performance. The electrolyte compositions include mixed lithium salts, mixed organics solvent, and a least one additive compounds. The mixed lithium salts system was selected from (1) inorganic salts, e.g., LiPF\({}_{6}\), LiBF\({}_{4}\); (2) lithium salt, e.g., lithium cyclic 1,2-ethanedisulfonylimide, lithium cyclic 1,3-propanediolsulfonylimide; (3) organic salts, e.g., LiN(CF\({}_{3}\)SO\({}_{2}\))\({}_{2}\), LiN(C\({}_{2}\)F\({}_{5}\)SO\({}_{2}\))\({}_{2}\), LiCF\({}_{3}\)SO\({}_{3}\). The mixed organic solvents comprised of four types of carbonates, e.g., ethylene carbonate (EC), propylene carbonate (PC), and vinylene carbonate (VC) were widely used. Additives, e.g., cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are used to prevent overcharge. The other patent was US6942949B2 (published on 13 September 2005) by LG Chem. Inorganic salts, e.g., LiPF\({}_{6}\), LiClO\({}_{4}\), and organic salts e.g., LiN(CF\({}_{3}\)SO\({}_{2}\))\({}_{2}\) are used together. EC, PC, and other carbonates (e.g., EMC, DEC, DMC) are also used as a mixed solvents system. The electrolyte solutions were similar to the aforementioned patent US7083878B2 with the difference in the additive, where 1,5-hexadiene, cyclohexene, and 4-vinylcyclohexene were used to be first oxidized at the cathode at a potential range over 4.3 V vs. Li/Li\({}^{+}\) to form a passivation layer on the cathode material. With these additives in the electrolyte, the negative effects, such as structural deformation of the cathode or excess consumption  
Figure 3: Top 10 patents with high forward-citation counts.  
of the electrolyte caused by overcharge could be prevented. More compositional information in the electrolyte disclosed by these two patents can be referred to Table 2. Complete information about the top 10 patents with high forward-citation counts can be found in Table S1 in the Supplementary Materials.  
Among these patents, the invention of US6852450B2 is about a lithium-sulfur battery. Samsung used an additive in the gas form, e.g., CO\({}_{2}\), SO\({}_{2}\), and N\({}_{2}\)O to improve the cycle life with the forming of a SEI film on the surface of a negative electrode. From the above discussion, lithium inorganic/organic salts and carbonate solvents are believed still to be commonly uses in LIBs. Novel additive compounds are still an important factor to improve/enhance the performance of LIBs.