Table 2.

The orthogonal experimental design and analysis for sodium metal batteries.

Factors and levels of the orthogonal L9 (34) test
Levels	Factors
	A (Salts)	B (msalt: mPEO + 21-β-CD-g-PTFEMA, %)	C (mPEO: m21-β-CD-g-PTFEMA)	D (Mn, GPC (21-β-CD-g-PTFEMA), g·mol−1)
1	NaPF6	10	2: 1	100k
2	NaClO4	15	3: 1	800k
3	NaTFSI	20	4: 1	900k

Evaluation indices of the orthogonal L9 (34) test
Orthogonal indices	Factors
	A	B	C	D
K1 (%) (a)	61.4	58.4	44.5	60.5
K2 (%) (a)	62.4	86.2	79.0	62.6
K3 (%) (a)	83.7	63.0	84.1	84.4
R (b)	0.223	0.278	0.396	0.239
Order of Importance	C > B > D > A
Optimal Level	A3	B2	C3	D3
Optianl Composition	mNaTFSI: mPEO + 21-β-CD-g-PTFEMA = 15% mPEO: m21-β-CD-g-PTFEMA = 4: 1 Mn, GPC (21-β-CD-g-PTFEMA) = 900 kg mol−1 MPEO = 600 kg mol−1

^a${\mathrm{K}}_{\mathrm{i}}^{\mathrm{F}}=\frac{1}{3}\left(\sum \mathrm{value}\mathrm{of}\mathrm{evalution}\mathrm{indexes}\mathrm{at}\mathrm{the}\mathrm{same}\mathrm{level}\mathrm{for}\mathrm{each}\mathrm{factor}\right)$.

^b${\mathrm{R}}^{\mathrm{F}}=\max \left\{{\mathrm{K}}_{\mathrm{i}}^{\mathrm{F}}\right\}-\min \left\{{\mathrm{K}}_{\mathrm{i}}^{\mathrm{F}}\right\}$, where F stands for the different factors (A, B, C, and D) and i stands for the different levels (1, 2, and 3).