• Samples 1-6 are cycled Lithium-ion battery electrodes

• Samples 7-8 are control electrode materials that have not been cycled and therefore have no SEI layer.

• All samples except 8 are Li4Ti5O12 /carbon black /PTFE on copper electrode coin cell (12mm diameter).

• For sample s 1-3 the electrolyte was LITFSI in water with Li2(NO)3 additive for samples 4-6 the electrolyte was LiPF6 in EC/DMC with THF additive

Sample key (including sample dimensions)

1= cycled 2 times, discharged (14 mm diameter coin cell)

2=cycled 50 times, discharged (14 mm diameter coin cell)

3=cycled 2 times, charged (14 mm diameter coin cell)

4= cycled 2 times, discharged (14 mm diameter coin cell)

5= cycled 2 times, charged (14 mm diameter coin cell)

6= cycled 50 times, discharged (14 mm diameter coin cell)

7= control electrode, not cycled (1cm x 1cm wafer)

8=control electrode same as 7 but with CMC instead of PTFE as binder (1cm x 1cm wafer)

High resolution Elements to run for samples 1-8

Li, S, P, Co, Fe. (Note C 1s, O 1s, and Survey spectra are run by default)

Any additional information

· Please also include additional info here such as do only some of the samples need sputtering, do samples need different amounts of sputtering due to different film thicknesses?

· Also, any other experimental details such as heating order of running etc…..

· Please indicate any elements that are in particularly low concentration so that we can run enough scans to get reasonable signal to noise.