## 7 Challenges  
Although PDCs demonstrate superior performance compared to conventional graphite anodes, their practical implementation faces critical challenges that necessitate systematic solutions. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Samples** & \begin{tabular}{c} **Free Carbon** \\ **[wt\%]** \\ \end{tabular} & \begin{tabular}{c} **C\({}_{rev}\)** \\ **[mAh\(\cdot\)g\({}^{-1}\)]** \\ \end{tabular} & \
\begin{tabular}{c} **\(C_{itr}\)** \\ **[mA\(\cdot\)g\({}^{-1}\)]** \\ \end{tabular} &
\begin{tabular}{c} **Cycling Current** \\ **[\%]** \\ \end{tabular} & **Capacity** & **Ref.** \\ \hline SiO\({}_{1.5}\)C\({}_{3.9}\) & 44.3 & 640 & 340 & 65 & 14.8 & n.d. & [30] \\ SiO\({}_{0.51}\)C\({}_{7.78}\) & 65.2 & 608 & 259 & 70 & 32.7 & 95\% after 40 cycles & [61] \\ SiO\({}_{0.85}\)C\({}_{1.99}\) & 25.9 & 794 & 370 & 68 & 100 & n.d. & [71] \\ SiO\({}_{0.90}\)C\({}_{4.40}\) & 48.5 & 568 & 330 & 63 & 18 & cycling stable & [72] \\ SiO\({}_{0.98}\)C\({}_{2.47}\) & 32.0 & 605 & 325 & 65 & 18 & cycling stable & [31] \\ SiO\({}_{1.98}\)C\({}_{3.36}\) & 43 & 600 & 680 & 47 & 360 & cycling stable & [73] \\ SiO\({}_{1.18}\)C\({}_{5.52}\) & 54.2 & 504.3 & 287.1 & 63.7 & 37 & 68.8\% after 60 cycles & [66] \\ SiO\({}_{0.95}\)C\({}_{3.72}\) & 43.6 & 535.9 & 335.8 & 61.5 & 37 & 56.0\% after 60 cycles & [66] \\ SiO\({}_{1.01}\)C\({}_{2.93}\) & 36.8 & 434.3 & 273.8 & 61.3 & 37 & 58.7\% after 60 cycles & [66] \\ SiO\({}_{0.93}\)C\({}_{2.26}\) & 29.5 & 501.4 & 302.7 & 62.3 & 37 & 47.3\% after 60 cycles & [66] \\ SiO\({}_{0.87}\)C\({}_{1.62}\) & 20.6 & 682.5 & 495.8 & 57.9 & 37 & 13.5\% after 60 cycles & [66] \\ SiO\({}_{1.00}\)C\({}_{1.05}\) & 11.6 & 706.1 & 375.5 & 65.3 & 37 & 5.2\% after 60 cycles & [66] \\ SiO\({}_{1.40}\)C\({}_{0.70}\) & 8.1 & 500.7 & 754.6 & 39.9 & 37 & 1.5\% after 60 cycles & [66] \\ SiO\({}_{5.38}\)N\({}_{0.98}\)O\({}_{0.19}\) & 57.04 & 383 & 172 & 69 & 18 & cycling stable & [46] \\ SiC\({}_{3.70}\)N\({}_{0.69}\)O\({}_{0.62}\) & 46.02 & 241 & 291 & 45 & 18 & cycling stable & [45] \\ SiO\({}_{0.06}\)C\({}_{1.54}\)N\({}_{0.74}\) & 23.2 & 69 & 67 & 50.6 & 18.6 & 127.5\% after 114 cycles & [74] \\ SiO\({}_{0.05}\)C\({}_{2.22}\)N\({}_{0.84}\) & 33.4 & 278 & 199 & 58.3 & 18.6 & 112.9\% after 114 cycles & [74] \\ SiO\({}_{1.00}\)C\({}_{4.04}\)N\({}_{0.69}\) & 49.3 & 374 & 227 & 60.5 & 18.6 & 115.9\% after 114 cycles & [74] \\ SiC\({}_{3.90}\)O\({}_{1.N_{0.8}}\) & 48 & 703 & 375 & 65 & 18 & 89\% after 134 cycles & [52] \\ SiC\({}_{1.05}\)O\({}_{1.56}\)N\({}_{0.21}\) & 69.1 & 570 & 367 & 61 & 18 & cycling stable & [75] \\ SiC\({}_{3.70}\)O\({}_{1.N_{1}}\)H\({}_{0.9}\) & 48.1 & 674 & 525 & 56 & 18.6 & 68\% after 134 cycles & [47] \\ SiC\({}_{3.03}\)N\({}_{1.2}\)H\({}_{0.2}\) & 56.0 & 282 & 224 & 56 & 18.6 & 109\% after 134 cycles & [47] \\ SiOC-pypyil & 37.5 & 793 & 394 & 67 & 100 & cycling stable & [76] \\ SiOC-pyil & 14.3 & 687 & 660 & 51 & 100 & cycling stable & [76] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The effect of free carbon on the performance of lithium-ion batteries. The free carbon content, first-cycle reversible capacity (Crev), irreversible capacity (Cirr) and coulombic efficiency (n) as well as cycling current and if available capacity retention upon continuous cycling are listed (n.d. = not determined) [62]. 1. Capacity Limitation of Silicon-Glass Phases: The intrinsic properties of silicon-based glass phases inherently restrict capacity enhancement. While amorphous structures exhibit suboptimal long-term cycling stability and conductivity, strategic modifications--such as boron (B) and nitrogen (N) doping or composite design--can improve interfacial stability. Notably, the synergistic effects of multi-element doping (e.g., B-N co-doping) remain underexplored and warrant systematic investigation to unlock higher capacity retention. 2. Low Initial Coulombic Efficiency (ICE): The persistently low ICE (50-70%) severely hinders commercial viability.